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Speaker 1: Hey, welcome to Stuff to Blow your Mind. It's Robert

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Speaker 1: Lamb again and we have another Vault episode for you.

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Speaker 1: This is part three of our series from last year

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Speaker 1: on Horror vacuu I I hope you enjoy.

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Speaker 2: Welcome to Stuff to Blow your Mind production of iHeartRadio.

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Speaker 1: Hey you welcome to Stuff to Blow your Mind. My

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Speaker 1: name is Robert Lamb.

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Speaker 3: And I'm Joe McCormick, and we're back with part three

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Speaker 3: of our series on Horror Vacui or Fear of the Void,

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Speaker 3: which we have. We've been mainly focusing I think on

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Speaker 3: art and design in the past couple of episodes, but

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Speaker 3: today I wanted to take a look at the history

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Speaker 3: of the vacuum, and specifically resistance to the idea of

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Speaker 3: the vacuum in philosophy and physics. And to begin, I

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Speaker 3: was reading at the scientific history of vacuum physics in

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Speaker 3: a book called The Void by Frank Close from Oxford

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Speaker 3: University Press in two thousand and seven. Frank Close is

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Speaker 3: a professor of physics at Oxford. I think emeritis now,

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Speaker 3: but anyway, I was reading about this and he included

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Speaker 3: a quote from the rig Veda that I thought was

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Speaker 3: very interesting. This is from the creation Hymn of the

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Speaker 3: rig Veda, which says, in translation, there was neither non

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Speaker 3: existence nor existence. Then there was neither the realm of

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Speaker 3: space nor the sky, which is beyond what stirred where?

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Speaker 3: And I really like this because it I think it

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Speaker 3: encapsulates a kind of a fascinated but challenging history of

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Speaker 3: attempts to conceptualize empty space, to even imagine what empty

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Speaker 3: space would mean if it were to exist, Because I

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Speaker 3: noticed kind of a gap here. As far as I

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Speaker 3: can tell, most people all around the world today, even

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Speaker 3: in various different cultures whatever, really, as far as I

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Speaker 3: can tell, don't seem to express any major problems making

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Speaker 3: sense of the idea of empty space. Obviously, there is

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Speaker 3: a lot we don't know about the nature of space.

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Speaker 3: What is space, where does it come from? What different

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Speaker 3: kinds of space could there be, and so forth. So

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Speaker 3: space is still a vessel of many mysteries. It's not

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Speaker 3: like we've got it all solved. But if you just

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Speaker 3: simplify the idea to the basics, I and I think

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Speaker 3: most people don't have any problem imagining the concept of

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Speaker 3: an area of three dimensional space with no particles in it.

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Speaker 3: That just yeah, Okay, that makes sense as an idea

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Speaker 3: to me. But if you read about how ancient Greek

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Speaker 3: philosophers wrote about this question, I do not get the

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Speaker 3: impression that the same was generally true for them. Not

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Speaker 3: only did many of them deny the possibility of empty

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Speaker 3: space existing, sometimes I get the feeling that they are

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Speaker 3: struggling to even imagine what the concept would mean. Do

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Speaker 3: you know what I'm getting at here, Rob.

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Speaker 1: Yeah, Yeah, this is something we talked a little bit

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Speaker 1: about off Mike before the episode here. Yeah, it's it's

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Speaker 1: kind of complicated. I mean, one level, they're always going

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Speaker 1: to be linguistic possibilities in play. For example, I was

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Speaker 1: looking into some sources on the void in Chinese philosophy,

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Speaker 1: and you run into, for example, that they are separate

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Speaker 1: terms for such concepts as emptiness, nothingness, and the infinite

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Speaker 1: or the absolute and one source here, I was looking

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Speaker 1: at Fan Magois in Frontiers of Philosophy in China from

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Speaker 1: twenty ten, contents that their subtleties involved that quote English

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Speaker 1: language is unable to capture. So yeah, we have to

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Speaker 1: acknowledge linguistic possibilities. But on the other hand, like thinking

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Speaker 1: about like what is it as a modern human, Like,

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Speaker 1: why do I, like, you have no problem imagining a

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Speaker 1: vacuum or or even a void. And I think part

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Speaker 1: of it may be like just the mechanical possibilities that

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Speaker 1: we have now and the media evidence thereof. So for instance,

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Speaker 1: when I think about a perfect vacuum, I can imagine

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Speaker 1: a device that mechanically makes it so within say a

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Speaker 1: closed space, I can think back to footage of someone

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Speaker 1: in a It's not a perfect vacuum, but a place

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Speaker 1: that has no air, that's sort of vacuum. Because I

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Speaker 1: guess we get into differences too. Are we talking about

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Speaker 1: a space without air in which say a scientist in

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Speaker 1: a suit may drop a feather and a bowling ball

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Speaker 1: and do that whole experiment, or are we talking about

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Speaker 1: something that is a true vacuum with nothing in it

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Speaker 1: at all, like like an absolute void. And there are

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Speaker 1: differences there, but yeah, as far as just like maybe

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Speaker 1: it gets into the idea of imagining a space with

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Speaker 1: air in it, Like we have this clear idea of

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Speaker 1: what atmosphere is and what air is, and we can

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Speaker 1: also see and behold and sort of to some degree

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Speaker 1: understand the mechanics by which that air may be removed

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Speaker 1: from a space, and therefore you could have a space

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Speaker 1: where the visible is not present and the invisible has

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Speaker 1: been removed as well.

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Speaker 3: Yeah, that's a very good point. And I think, for like,

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Speaker 3: one major difference may be the unsettled question of like

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Speaker 3: whether the air itself has weight for much of human history. Like,

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Speaker 3: if you don't have that worked out, it may just

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Speaker 3: be harder to imagine what space devoid of even gas

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Speaker 3: particles would be. Yeah, but I want to turn to

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Speaker 3: some examples that Frank Close looks at in this book,

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Speaker 3: especially his first chapter on sort of the ancient history

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Speaker 3: of the void in physics, to look at how this

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Speaker 3: idea was thought of before the modern era. So the

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Speaker 3: pre Socratic Greek philosopher Thales of Militias, who lived from

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Speaker 3: the seventh to the sixth century BCE, writing about the

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Speaker 3: idea of emptiness or void without substance, is actually kind

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Speaker 3: of tempted to ask can there be such a thing

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Speaker 3: as nothing? If someone is able to think about it,

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Speaker 3: wouldn't thinking about it mean it was something? And again

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Speaker 3: this raises an interesting question for me. I mean, my

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Speaker 3: initial reaction is just like, well, no, you know, so

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Speaker 3: imagine a container with empty space in it. I don't

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Speaker 3: think by thinking about that we change the nature of

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Speaker 3: what's in the container. But this does kind of raise

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Speaker 3: the specter of like if there could be a vacuum

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Speaker 3: for people like Thelees. Maybe this has almost more sort

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Speaker 3: of totalizing cosmic implications, that the ability of a vacuum

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Speaker 3: to exist says something about the universe as a whole,

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Speaker 3: not just one region of the universe, say inside of

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Speaker 3: a glass bottle or something. So that's one level in

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Speaker 3: which I respond. But then on the other hand, I

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Speaker 3: can sympathize with thoughts like this knowing some things about

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Speaker 3: modern physics, because in a very real sense, empty space

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Speaker 3: is I think I can make the argument that it

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Speaker 3: is not nothing. Empty space is something even though it

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Speaker 3: is not matter. So this may come from a failure

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Speaker 3: to distinguish between space and a concept like nothingness, in

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Speaker 3: which case, like if you're imagining space is something like

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Speaker 3: space has properties, then in fact it couldn't be nothing,

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Speaker 3: which is what Theyley's was thinking about.

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Speaker 1: Yeah, this perhaps distinction between nothingness and emptiness, this whole

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Speaker 1: thing about thinking about it making it maybe less nothing.

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Speaker 1: This reminds me of another paper I was looking at

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Speaker 1: being in nothingness in Greek and ancient Chinese philosophy by

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Speaker 1: Giming shein Philosophy East and West, nineteen fifty one. This

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Speaker 1: author points out that in both Chinese Taoism and Greek philosophy,

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Speaker 1: you see this culmination of things in nothingness. Quote, nothingness

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Speaker 1: is the nature of being in itself, which is absolutely

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Speaker 1: transcendent and nameless. So if I'm interpreting this correctly, the

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Speaker 1: sort of dual identity of nothingness in these two different

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Speaker 1: thought systems, nothingness is ultimately that which comes before substance,

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Speaker 1: but also comes before human attributed meaning. So yeah, like

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Speaker 1: even thinking about even giving it a name changes the

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Speaker 1: nothingness of it, at least from these perspectives.

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Speaker 3: Yes, though with Greek philosophy, I know it very much

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Speaker 3: depends on which philosopher you're talking about, because a lot

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Speaker 3: of these big Greek philosophers, they were emphatic in specifically

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Speaker 3: rejecting the idea that the universe could have come from nothingness,

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Speaker 3: that there could ever have been nothingness, or that the

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Speaker 3: universe would ever disappear into nothingness like that was specifically

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Speaker 3: part of what the cosmological history that Theales was arguing for.

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Speaker 3: According to Thales, it would be impossible for the universe

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Speaker 3: to have come from nothingness, and it would be impossible

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Speaker 3: for it to ever become nothing. There's just sort of

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Speaker 3: like infinitely the same.

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Speaker 1: Stuff without giving into the exacts of it all though,

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Speaker 1: when you hear some of these sweeping x nations of what, say,

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Speaker 1: the universe would be if it were reduced to a singularity,

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Speaker 1: you know that sort of thing like, that's not nothing,

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Speaker 1: it's something, but it's such a strange and alien concept,

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Speaker 1: so different from certainly our perceivable reality, that it might

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Speaker 1: as well be nothing, you know.

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Speaker 3: Yes, that's a good point. And of course, again to

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Speaker 3: highlight the difference between nothingness and empty space. Nothingness, I

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Speaker 3: think is much harder to define. I don't know exactly

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Speaker 3: what we mean when we talk about nothingness. It's sort

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Speaker 3: of a more slippery, mysterious concept. Whereas empty space. Again,

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Speaker 3: it's not that we understand everything about it, but it

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Speaker 3: is something that has physical properties and can be manipulated.

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Speaker 3: We know some things about.

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Speaker 1: It, yeah, like even linguistically. When we talk about vacuum,

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Speaker 1: so we've formed an artificial vacuum inside of a reinforced

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Speaker 1: steel chamber. Does that steel chamber contain a vacuum, and

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Speaker 1: therefore the vacuum is not nothing because it is a

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Speaker 1: thing by virtue of being different from everything surrounding it

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Speaker 1: because it is contained.

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Speaker 3: Yeah. Yeah, well that raises another question of when you

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Speaker 3: ask whether a vacuum exists in nature, I mean in reality,

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Speaker 3: Whenever we're talking about a vacuum, we're talking about essentially

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Speaker 3: low density gas. So and the question is how low

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Speaker 3: density does the gas have to get before you are

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Speaker 3: comfortable talking about a region of it as a vacuum.

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Speaker 3: So like and say the and we can come back

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Speaker 3: to this maybe in the next part of the series

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Speaker 3: or something. But like in interstellar voids, there are still

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Speaker 3: particles floating around out there. They're just very far apart

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Speaker 3: compared to much closer to stars or in the atmosphere

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Speaker 3: of a planet. But I guess the question would be

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Speaker 3: how far apart does every individual particle of matter have

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Speaker 3: to get before you say, okay, this is really a

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Speaker 3: total vacuum. But to come back to Theales for a second,

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Speaker 3: close makes an interesting argument about Thales sort of having

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Speaker 3: something in his cosmology similar to to a kind of

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Speaker 3: empty space, basically a primeval material or a sort of

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Speaker 3: ground state for the universe, and Close argues that for Theyales,

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Speaker 3: this ground state of existence was water. This belief is

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Speaker 3: related to the fact that we can observe water going

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Speaker 3: through phase changes, so we can see water as solid ice,

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Speaker 3: as liquid, as water vapor. And Close says that Theales

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Speaker 3: assumed that the diversity of forms went on from there,

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Speaker 3: and in fact water was the basis of every material

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Speaker 3: on Earth. Rocks, plants, air, et cetera. Are all somehow

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Speaker 3: water in some extrapolated form, and so he writes, quote,

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Speaker 3: space for Theales is as empty as it can be

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Speaker 3: when all matter in it has been turned into its

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Speaker 3: primeval form, liquid water, like the ocean. Water thus contains

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Speaker 3: every possible form of matter.

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Speaker 1: I think we've actually discussed this before. Yeah, in connection

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Speaker 1: to his work, like you get down to the idea

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Speaker 1: of cosmic ocean, of a primordial ocean on which there

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Speaker 1: is no land and no being.

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Speaker 3: So there are definitely similarities between imagining, say, you know,

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Speaker 3: the gods or the Creator or whatever hovering over a

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Speaker 3: great void and hovering over a great ocean. That those

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Speaker 3: are like similar ideas in some of these ancient cosmologies

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Speaker 3: at least, But anyway, going on from there in the

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Speaker 3: fifth century BCE. There's another pre Socratic Greek philosopher, Impedicles,

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Speaker 3: who argued that there were actually four fundamental forms of matter.

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Speaker 3: It wasn't that everything came from water like they least

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Speaker 3: thought that there was in fact earth, air, fire, and water.

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Speaker 3: And Empedocles notably realized that air was itself a substance

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Speaker 3: and not merely empty space. He also believed there was

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Speaker 3: no such thing as empty space. But of course the

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Speaker 3: discovery that air is not empty space does not mean

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Speaker 3: that empty space cannot exist. But then we come to

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Speaker 3: the atomists, who are very interesting in their departure from

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Speaker 3: these other ways of thinking. So the atomists included a

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Speaker 3: number of ancient philosophers like Lucippus, Democritus, and Epicurus, who believed,

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Speaker 3: quite remarkably ahead of their time, that all matter is

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Speaker 3: actually made up of imperceptibly tiny particles, which they called atoms,

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Speaker 3: from the Greek word atomos, which is derived from something

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Speaker 3: that means like cannot be cut or basically indivisible. Now,

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Speaker 3: of course, today we know that atoms are not actually indivisible.

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Speaker 3: They are made up of subatomic particles like protons, neutrons, electrons,

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Speaker 3: and even protons and neutrons can be further subdivided, but

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Speaker 3: ancient atomists did not have the experimental apparatus needed to

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Speaker 3: discover this. Instead, they arrived at the atomic view of

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Speaker 3: physics primarily by way of thought, experiments, and everyday empirical observations,

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Speaker 3: such as the observation of things like the erosion of

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Speaker 3: solid matter in nature. So if you have a great,

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Speaker 3: a grand marble staircase, and you notice that over the years,

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Speaker 3: the steps on the staircase are eroding. They're sort of

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Speaker 3: like sagging in the places where people walk on them. Well,

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Speaker 3: they're solid marble. Where are they going? How do marble

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Speaker 3: steps wear away over the ages? It must be because

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Speaker 3: each person who steps on them removes some tiny, invisibly

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Speaker 3: small amount of matter. But that invisibly small amount of matter,

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Speaker 3: those little atoms that are taken away accumulate over time

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Speaker 3: and the steps are worn down. But importantly for this discussion,

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Speaker 3: the atomists believed that there actually is such a thing

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Speaker 3: as empty space. In fact, it was core to their

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Speaker 3: theory that the universe was composed of atoms in motion.

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Speaker 3: Those atoms in motion needed a space through which to move,

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Speaker 3: and the atomists argued that if there were already something

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Speaker 3: in the place an atom was moving too, the atom

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Speaker 3: couldn't move there because then two atoms would be occupying

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Speaker 3: the same space at once. So there had to be

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Speaker 3: such a thing as empty space. That was the only

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Speaker 3: way that such space could come to be occupied. You know,

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Speaker 3: there has to be space for things to move into

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Speaker 3: where nothing can move. But after this we get back

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Speaker 3: to Aristotle, because we mentioned him at the beginning of

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Speaker 3: the first episode in this series. For better or worse,

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Speaker 3: Aristotle would pretty much have the last word on this

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Speaker 3: question for centuries to come, until experiments in the seventeenth

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Speaker 3: century would strongly challenge his decree. But Aristotle says there

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Speaker 3: is no such thing as empty space. And I was

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Speaker 3: reading about the Aristotelian framework or foundation for the science

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Speaker 3: of the early modern period in the Cambridge History of Science,

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Speaker 3: volume three, edited by Lindberg at All. This was in

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Speaker 3: a chapter called Physics and Foundations by the Princeton philosopher

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Speaker 3: Daniel Garber, and he makes some interesting points. But reading

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Speaker 3: this chapter, this is the way I was thinking about it.

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Speaker 3: So when we think of physics today, we usually of

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Speaker 3: it as a science contained within certain boundaries, like there

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Speaker 3: are certain kinds of questions that are physics questions, and

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Speaker 3: there are other questions that are not physics. Is the

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Speaker 3: study of properties of matter and energy something like that,

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Speaker 3: and that's a huge field, so you can ask tons

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Speaker 3: of questions in it, like how are stars formed? Or

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Speaker 3: what is the relationship between particle mass and the Higgs field.

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Speaker 3: But if in a physics journal today you tried to

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Speaker 3: submit a paper on a question like what are the

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Speaker 3: basic modes of existence? And what is being? And what

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Speaker 3: is the relationship of those things? To say, God, this

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Speaker 3: would probably be rejected as outside the scope of the

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Speaker 3: physical sciences, you know, like the editors would say, you

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Speaker 3: need to submit this to a different journal. However, this

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Speaker 3: attempted limitation of scope was not always present in fields

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Speaker 3: analogous to physics. Throughout history. There are many times in

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Speaker 3: history where these things really kind of blend together, or

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Speaker 3: at least philosophical foundations are thought to have relevant things

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Speaker 3: to say about physics theories. So these philosophical foundations might

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Speaker 3: include religious worldviews. So you could think about the way

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Speaker 3: that the scientists of the Islamic world in the Middle

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Speaker 3: Ages might have thought of Islam as a theological foundation

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Speaker 3: for the sciences or the way that Christian natural philosophers

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Speaker 3: of Europe might have thought about Christianity in the same way.

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Speaker 3: But in the West there was a major secular philosophical

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Speaker 3: foundation of early science also, and that was Aristotelianism, the

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Speaker 3: philosophy of Aristotle and a fourth century BCE Greek philosopher.

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Speaker 3: And I think it's fair to say that for like

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Speaker 3: hundreds of years, in the schools and universities of medieval

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Speaker 3: through early modern Europe, the philosophy of Aristotle was not

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Speaker 3: taught in the way that it would be taught in

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Speaker 3: a college class today. Like today you would teach it

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Speaker 3: like here is an interesting piece of intellectual history, maybe

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Speaker 3: providing a certain point of view and showing the development

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Speaker 3: of how people thought about X, Y or z. Instead,

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Speaker 3: I think it was often taught in a way that

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Speaker 3: was closer to how people would have thought about the Bible.

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Speaker 3: It's like Aristotle said it. That pretty much settles it.

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Speaker 1: Yeah, yeah, So you end up with various discussions and

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Speaker 1: arguments coming down to either what Aristotle said or disagreements

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Speaker 1: over what Aristotle did say or meant, or what he

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Speaker 1: would have said or meant about a given topic.

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Speaker 3: Right, and to be clear, it wasn't always this way,

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Speaker 3: but it wasn't that everybody thought Aristotle was literally infallible.

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Speaker 3: But it seems to me like he was often treated

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Speaker 3: by the Scholastics as something approaching infallibility, like it was

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Speaker 3: just ludicrous to question Aristotle, though in some cases people did.

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Speaker 1: So.

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Speaker 3: We should discuss what Aristotle said as about the void.

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Speaker 3: Aristotle denies the possibility of the existence of empty space,

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Speaker 3: specifically in his book Physics Book four, and as is

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Speaker 3: so often true with these ancient philosophers, he makes his

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Speaker 3: case for the non existence of a vacuum not by

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Speaker 3: doing an experiment and describing it, but by cold rationiocination.

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Speaker 3: He is going to reason his way out of having

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Speaker 3: to believe in empty space. Garber, in his chapter quotes

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Speaker 3: a translation of Aristotle for one of his arguments along

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Speaker 3: these lines. Aristotle says, now it space or place has

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Speaker 3: three dimensions length, breadth, depth, the dimensions by which all

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Speaker 3: body is bounded. But the place cannot be body, for

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Speaker 3: if it were, there would be two bodies in the

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Speaker 3: same place. What in the world then, are we to

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Speaker 3: suppose place to be? And the implied answer is nothing,

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Speaker 3: So not to kind of interesting contradiction. It seems to

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Speaker 3: me at least that we had the atomists pointing to

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Speaker 3: the fact that two objects can't be in the same

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Speaker 3: place at the same time to prove that there must

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Speaker 3: be empty space, because remember, moving particles have to have

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Speaker 3: unoccupied space to move into. And here Aristotle is using

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Speaker 3: the same premise in a way to say that space

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Speaker 3: cannot exist independent of matter, or else it would have

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Speaker 3: to occupy the same place as matter at the same time.

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Speaker 3: But coming back to close, he summarizes Aristotle's arguments by saying, quote,

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Speaker 3: so for Aristotle, logics seem to require that empty space

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Speaker 3: cannot be something and therefore is non existent. He defined

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Speaker 3: the void as where there is no body, and since

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Speaker 3: the basic elements of things exist eternally, there can be

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Speaker 3: no place that is completely empty. Aristotle may have been

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Speaker 3: getting some mileage here out of confusion over the difference

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Speaker 3: between empty space as something and like nothingness as in

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Speaker 3: a way meaning non existence.

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Speaker 1: Now.

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Speaker 3: Garber, in his Physics and Foundations chapter writes that by

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Speaker 3: the thirteenth century, writers in the Scholastic tradition in Europe

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Speaker 3: who believed in Aristotelian dogmas had begun assuming the existence

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Speaker 3: of a natural force known as horror vacui, again a

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Speaker 3: phrase that Aristotle himself did not use, but which aligned

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Speaker 3: with his teaching on this matter, that nature would not

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Speaker 3: permit a vacuum, and the scholastic writers characterize this as

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Speaker 3: a force in nature which prevents vacuo from emerging, almost

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Speaker 3: like there's sort of a law of nature something going

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Speaker 3: on that will not let a vacuum be created, and

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Speaker 3: thus forces matter to fill in the gaps. So you

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Speaker 3: can pump out that container as much as you want,

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Speaker 3: but horror vacue will prevent it from actually being empty inside.

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Speaker 3: And another interesting thing I wanted to flag here is

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Speaker 3: that Garber notes a conflict between this Aristotelian dogma and

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Speaker 3: some religious reasoning that arose in the Church in the

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Speaker 3: thirteenth century that have led to the famous condemnations of

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Speaker 3: twelve seventy seven, where we've got a bishop condemning Aristotle.

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Speaker 3: So to read from Garber here quote one consequence was

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Speaker 3: that without space outside of the finite world, not even

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Speaker 3: God would seem to be able to move the universe

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Speaker 3: if he chose to do so. This apparent consequence of

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Speaker 3: Aristotilian doctrine was rejected in the famous condemnation of Aristotle

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Speaker 3: by Etienne Tempier, the Bishop of Paris, in twelve seventy seven,

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Speaker 3: and then quoting in translation, here we condemned the proposition

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Speaker 3: that God could not move the heavens with rectilinear motion,

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Speaker 3: and the reason is that a vacuum would remain so

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Speaker 3: Garber says, this really kind of put these scholastic Aristotilians

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Speaker 3: in a bind, because in some ways they had to

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Speaker 3: defend the possibility of some kind of empty space existing

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Speaker 3: in the universe, at least potentially for theological reasons, but

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Speaker 3: they didn't want to vile the principles of Aristotle, to

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Speaker 3: which they were loyal. But anyway, going on, Frank Close

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Speaker 3: makes an interesting argument that I think I would agree

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Speaker 3: with that we shouldn't be too hard on the prevailing

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Speaker 3: Aristotelian belief in horror vacae because without special equipment and experiments,

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Speaker 3: I don't know, it really just seems like that from

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Speaker 3: everyday existence, like it seems like reality prevents voids from forming.

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Speaker 3: Examples given by the ancient philosophers were things like, hey,

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Speaker 3: you suck all the air out of an empty wine skin,

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Speaker 3: the wine skin collapses like it shrinks in removing the

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Speaker 3: air does not result in a void inside the skin.

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Speaker 3: It causes the walls of the skin to shrink proportional

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Speaker 3: to the amount of air you're able to remove. You

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Speaker 3: could also use this belief in nature's hatred for the

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Speaker 3: vacuum to explain the workings of pumps and siphons. So

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Speaker 3: beyond the fact that Aristotle said it, it just kind

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Speaker 3: of seemed right with everyday experience.

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Speaker 1: Yeah, I mean, and you're not walking around your home

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Speaker 1: and just suddenly walking into a vacuum, right, Like, even

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Speaker 1: the empty rooms are are full, They're teeming with matter.

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Speaker 1: And these are I think all great examples where you

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Speaker 1: could you can imagine someone saying, look proof right here,

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Speaker 1: look at this wine skin. If you can form a

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Speaker 1: void in this wide skin, then I'll believe you. Otherwise,

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Speaker 1: absolutely not.

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Speaker 3: So while horror vakae had its critics for a long time,

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Speaker 3: I think it's safe to say that it was really

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Speaker 3: like the seventeenth century where this idea was laid to rest.

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Speaker 3: So coming back to this idea of like when you

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Speaker 3: suck on a straw, what is the force that actually

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Speaker 3: causes the liquid in your drink to rise up the

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Speaker 3: straw into your mouth. You could imagine it as a

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Speaker 3: vacuum created that like sort of resists formation and thus

414
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Speaker 3: sucks the liquid up. The same question was actually raised

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Speaker 3: around the year sixteen hundred and brought to the attention

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Speaker 3: of Galileo. There are some examples of read about this.

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Speaker 3: One is an example of I think a scientist sort

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Speaker 3: of at the time a natural philosopher who had been

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Speaker 3: trying to construct a big siphon and encountered problems at

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Speaker 3: a certain height of the siphon. But then I've also

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Speaker 3: read about an influence here being people digging wells and

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Speaker 3: mine shafts who would try to remove water from these pits,

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Speaker 3: using like plunger based pumps to lift the water out

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Speaker 3: through a pipe. There was a problem in all these

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Speaker 3: cases with the siphons and the pumps. Basically, the pumps

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Speaker 3: stopped working after a certain height after the water was

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Speaker 3: raised roughly ten point three meters or so, when you

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Speaker 3: had ten point three meters worth of a column in

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Speaker 3: the pipe, it would stop going higher, wouldn't climb the

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Speaker 3: pipe anymore, and instead a gap would appear between the

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Speaker 3: water column and the plunger or the piston or whatever

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Speaker 3: you're using to pump it out. So what's going on

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Speaker 3: here was what was actually limiting the height of the

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Speaker 3: water pump system. Well, Galileo investigated this question, and he

435
00:26:02,480 --> 00:26:06,320
Speaker 3: suspected that the force that drew water up through a

436
00:26:06,320 --> 00:26:09,679
Speaker 3: pump or a siphon may in fact be the force

437
00:26:10,000 --> 00:26:15,720
Speaker 3: of horror vacay. So the vacuum is resisting formation and

438
00:26:15,760 --> 00:26:19,160
Speaker 3: thus pulling water up after itself. So when you try

439
00:26:19,160 --> 00:26:21,960
Speaker 3: to run the pump, the fact that the universe is

440
00:26:22,040 --> 00:26:25,560
Speaker 3: resisting creating a vacuum in that space in between is

441
00:26:25,680 --> 00:26:26,920
Speaker 3: forcing water up.

442
00:26:27,200 --> 00:26:32,040
Speaker 1: I love how this also kind of implies that Galileo

443
00:26:32,280 --> 00:26:36,320
Speaker 1: was maybe not solving a physics problem, but responding to

444
00:26:36,359 --> 00:26:39,119
Speaker 1: a pump problem. We get Galileo on the horn. We

445
00:26:39,200 --> 00:26:40,920
Speaker 1: got a problem with this pump here. See if it

446
00:26:40,960 --> 00:26:42,399
Speaker 1: has time he's afternoon to look at it.

447
00:26:42,640 --> 00:26:45,680
Speaker 3: Well, I mean, that's a wonderful thing about Galileo. I mean,

448
00:26:45,680 --> 00:26:47,960
Speaker 3: he was at all ends of the spectrum right working

449
00:26:47,960 --> 00:26:51,879
Speaker 3: on theoretical problems and astronomy and everyday you know, mechanical

450
00:26:51,920 --> 00:26:56,320
Speaker 3: physics problems. But yeah, it is hilarious. Imagine. I don't

451
00:26:56,359 --> 00:26:59,199
Speaker 3: know exactly when this was first raised to him, but

452
00:26:59,400 --> 00:27:02,440
Speaker 3: it's fun to imagine somebody's like trying to get water

453
00:27:02,520 --> 00:27:04,960
Speaker 3: out of their basement or their mind shaft, and they

454
00:27:04,960 --> 00:27:08,040
Speaker 3: were just able to call up Galileo.

455
00:27:08,200 --> 00:27:10,240
Speaker 1: Or maybe he arrives at his end. He's like a superhero.

456
00:27:10,600 --> 00:27:14,040
Speaker 3: Yeah anyway, Yeah, so he imagines that maybe it is

457
00:27:14,119 --> 00:27:18,520
Speaker 3: the force of nature resisting the formation of a vacuum

458
00:27:18,840 --> 00:27:21,000
Speaker 3: that pulls the water up the pipe. But then at

459
00:27:21,040 --> 00:27:23,320
Speaker 3: a certain point, the weight of the water in the

460
00:27:23,400 --> 00:27:26,439
Speaker 3: pipe is too much. There's too much water, and the

461
00:27:26,520 --> 00:27:29,800
Speaker 3: vacuum resistance can't carry it any higher. It has reached

462
00:27:29,840 --> 00:27:34,280
Speaker 3: the limit of the strength of nature's resistance to a vacuum.

463
00:27:34,520 --> 00:27:38,280
Speaker 3: So fascinating question, but Galileo never solved it in his lifetime.

464
00:27:48,240 --> 00:27:50,280
Speaker 3: Enter a couple of other figures. We got a guy

465
00:27:50,359 --> 00:27:54,160
Speaker 3: named Gasparo Berti who lived sixteen hundred to sixteen forty three,

466
00:27:54,800 --> 00:27:59,240
Speaker 3: and Evangelista Torricelli sixteen oh eight to sixteen forty seven.

467
00:28:00,119 --> 00:28:02,639
Speaker 3: That rob I got a picture of Torricelli for you

468
00:28:02,720 --> 00:28:05,320
Speaker 3: to look at here. I think he is incredibly notable

469
00:28:05,359 --> 00:28:08,240
Speaker 3: for having a Batman symbol as a mustache.

470
00:28:08,640 --> 00:28:13,399
Speaker 1: Yeah, certain portraits of this guy have it worse than others,

471
00:28:13,440 --> 00:28:15,600
Speaker 1: but yet it has this I guess it's sort of

472
00:28:15,600 --> 00:28:21,199
Speaker 1: a Van Dyke, though in other portraits it really feels cruciform.

473
00:28:21,320 --> 00:28:23,880
Speaker 1: It feels like I mean, it looks like he took

474
00:28:23,920 --> 00:28:27,959
Speaker 1: a crucifix with flared arms and was perhaps kissing it

475
00:28:28,359 --> 00:28:33,200
Speaker 1: so much that the barber had to shave him around

476
00:28:33,240 --> 00:28:38,000
Speaker 1: that crucifix, resulting in this hairstyle. It's a lot.

477
00:28:38,520 --> 00:28:40,800
Speaker 3: I want my muzzle to make you think of the passion.

478
00:28:41,040 --> 00:28:44,440
Speaker 3: It seems. It is a bold look. So these two

479
00:28:44,440 --> 00:28:48,920
Speaker 3: Italian scientists, a Bertie and Torricelli performed similar experiments in

480
00:28:49,000 --> 00:28:52,480
Speaker 3: the early sixteen forties that would clarify what was going

481
00:28:52,520 --> 00:28:55,840
Speaker 3: on here. Bertie did an experiment with water, and then

482
00:28:55,920 --> 00:28:59,360
Speaker 3: several years later Torcelli did a more definitive and more

483
00:28:59,400 --> 00:29:04,600
Speaker 3: famous experiment with quicksilver, which we know today as elemental

484
00:29:04,840 --> 00:29:10,120
Speaker 3: liquid mercury. So Torricelli's experiment went like this. You would

485
00:29:10,120 --> 00:29:14,320
Speaker 3: get a glass tube about one meter long and fill

486
00:29:14,400 --> 00:29:18,840
Speaker 3: it completely with liquid mercury. So this tube would be

487
00:29:19,000 --> 00:29:22,160
Speaker 3: closed completely at one end and open at the other.

488
00:29:22,960 --> 00:29:25,680
Speaker 3: So you fill it with liquid mercury, and you temporarily

489
00:29:25,840 --> 00:29:28,840
Speaker 3: plug up the open end, so one end is permanently closed.

490
00:29:28,840 --> 00:29:31,080
Speaker 3: One end put a finger over it to close it,

491
00:29:32,000 --> 00:29:35,480
Speaker 3: and then you flip the tube upright vertical and sit

492
00:29:35,680 --> 00:29:39,520
Speaker 3: the open end down in a big basin of more

493
00:29:39,560 --> 00:29:41,560
Speaker 3: liquid mercury. So you got it like a tub of

494
00:29:41,560 --> 00:29:44,560
Speaker 3: liquid mercury. So you flip it up. You have the

495
00:29:44,560 --> 00:29:48,600
Speaker 3: the plugged open end facing down into the lake of mercury,

496
00:29:49,080 --> 00:29:52,480
Speaker 3: and then you unplug it. You remove the finger the plug. Now,

497
00:29:52,520 --> 00:29:56,200
Speaker 3: remember the tube started totally full of mercury, but now

498
00:29:56,240 --> 00:29:59,960
Speaker 3: that it's unplugged, the mercury can flow down into the

499
00:30:00,040 --> 00:30:03,200
Speaker 3: basin with the rest of the mercury. And when he

500
00:30:03,280 --> 00:30:06,480
Speaker 3: tried this, the mercury in the tube did fall, but

501
00:30:06,640 --> 00:30:09,960
Speaker 3: not all the way. It fell to leave a column

502
00:30:10,000 --> 00:30:13,719
Speaker 3: of mercury about seventy six centimeters in height, and then

503
00:30:13,760 --> 00:30:16,360
Speaker 3: a gap for the rest of the tube length up

504
00:30:16,440 --> 00:30:20,160
Speaker 3: at the closed top. So what was the gap, Well,

505
00:30:20,240 --> 00:30:24,719
Speaker 3: Torricelli reasoned that it was actually a vacuum. There was

506
00:30:24,800 --> 00:30:29,560
Speaker 3: effectively nothing inside the tube for those empty centimeters above

507
00:30:29,640 --> 00:30:34,280
Speaker 3: the column of mercury. The other guy, gasparo Berti, had

508
00:30:34,280 --> 00:30:37,959
Speaker 3: performed a similar experiment with water several years before, and

509
00:30:38,240 --> 00:30:42,160
Speaker 3: they both Both of these experiments seemed to provide evidence

510
00:30:42,240 --> 00:30:47,000
Speaker 3: that it was indeed possible for empty space to exist,

511
00:30:47,160 --> 00:30:50,440
Speaker 3: But the question remained, what was holding up the water

512
00:30:50,600 --> 00:30:53,800
Speaker 3: in the tube, and why would the water only rise

513
00:30:53,960 --> 00:30:56,720
Speaker 3: up the tube to a certain height, or, to put

514
00:30:56,760 --> 00:30:59,240
Speaker 3: it in another way, why would the liquid only fall

515
00:30:59,320 --> 00:31:03,400
Speaker 3: down to a certain consistent height in the tube. The

516
00:31:03,440 --> 00:31:07,000
Speaker 3: answer was also illuminated by Torricelli's experiment, for one thing,

517
00:31:07,160 --> 00:31:11,040
Speaker 3: by comparing the difference between the height of a water

518
00:31:11,160 --> 00:31:14,000
Speaker 3: column in a tube and the height of a mercury

519
00:31:14,000 --> 00:31:17,120
Speaker 3: column in a tube. They were different because water and

520
00:31:17,200 --> 00:31:22,239
Speaker 3: mercury have different densities, and so what Torricelli proposed, and

521
00:31:22,280 --> 00:31:25,160
Speaker 3: what in fact was correct, is that the force that

522
00:31:25,360 --> 00:31:28,480
Speaker 3: kept the water or the mercury column raised in the

523
00:31:28,480 --> 00:31:34,320
Speaker 3: tube was actually the force of atmospheric pressure, the pressure

524
00:31:34,400 --> 00:31:37,840
Speaker 3: of the air pushing down on the water or the

525
00:31:37,880 --> 00:31:42,640
Speaker 3: mercury in the basin below. And these tube systems assembled

526
00:31:42,680 --> 00:31:46,800
Speaker 3: by Birdie and Torricelli were actually systems for establishing an

527
00:31:46,880 --> 00:31:50,680
Speaker 3: equilibrium between the weight of the liquid in this column

528
00:31:50,720 --> 00:31:54,239
Speaker 3: in the tube and the weight the atmosphere exerts on

529
00:31:54,280 --> 00:31:57,120
Speaker 3: the liquid in the basin below. The liquid in the

530
00:31:57,120 --> 00:32:00,560
Speaker 3: sealed tube would fall until the weight of the column

531
00:32:00,600 --> 00:32:03,920
Speaker 3: was equal to the atmospheric pressure, and then it would

532
00:32:04,000 --> 00:32:07,760
Speaker 3: float and fall no more, leaving mostly a vacuum in

533
00:32:07,800 --> 00:32:11,200
Speaker 3: the space above. However, there was another question. There was

534
00:32:11,240 --> 00:32:14,280
Speaker 3: the question of what is causing this. It was important

535
00:32:14,320 --> 00:32:18,840
Speaker 3: to demonstrate that the vacuum was not the thing exerting

536
00:32:18,880 --> 00:32:22,440
Speaker 3: the force. Tori Shelley did this with another experiment involving

537
00:32:22,480 --> 00:32:26,960
Speaker 3: two mercury tubes, one with a sort of bulb on

538
00:32:27,080 --> 00:32:30,640
Speaker 3: the sealed top end. And the bulb would mean that

539
00:32:30,760 --> 00:32:34,520
Speaker 3: a greater volume of empty space was left at the

540
00:32:34,560 --> 00:32:38,040
Speaker 3: top when the liquid fell after the bottom was unplugged.

541
00:32:38,360 --> 00:32:41,200
Speaker 3: So would that make the mercury fall to a different level.

542
00:32:41,560 --> 00:32:43,720
Speaker 3: And it turns out the extra empty space did not

543
00:32:43,840 --> 00:32:47,320
Speaker 3: matter at all. The liquid fell to the same height regardless.

544
00:32:47,880 --> 00:32:50,760
Speaker 3: So the force exerted on the column of water in

545
00:32:50,840 --> 00:32:53,600
Speaker 3: the pipe or the tube was not a pull from

546
00:32:53,600 --> 00:32:56,200
Speaker 3: the vacuum. It was not a pull proportional to the

547
00:32:56,240 --> 00:33:00,160
Speaker 3: amount of vacuum created. It was a push proportional to

548
00:33:00,240 --> 00:33:04,600
Speaker 3: the relationship between the atmospheric pressure and the density of

549
00:33:04,600 --> 00:33:08,640
Speaker 3: the liquid. And this was further demonstrated in experiments performed

550
00:33:08,680 --> 00:33:12,640
Speaker 3: by Blaze, Pascal and I think with some input from Descartes,

551
00:33:13,280 --> 00:33:17,680
Speaker 3: but Blaize, Pascal and collaborators testing a similar experiment at

552
00:33:17,680 --> 00:33:20,480
Speaker 3: different altitudes, so you might you test it at the

553
00:33:20,480 --> 00:33:22,479
Speaker 3: foot of a mountain and then go up to the

554
00:33:22,480 --> 00:33:24,479
Speaker 3: top of a mountain and test again and see if

555
00:33:24,520 --> 00:33:27,680
Speaker 3: there are differences. And indeed they found that higher up

556
00:33:27,680 --> 00:33:30,400
Speaker 3: on a mountain, the column of mercury would be lower

557
00:33:30,440 --> 00:33:34,400
Speaker 3: because the atmospheric pressure was lower. And in fact, these

558
00:33:34,520 --> 00:33:38,960
Speaker 3: experiments and the apparatus used the apparatus what's the plural

559
00:33:38,960 --> 00:33:43,040
Speaker 3: of that, apparati or apparatuses. Anyway, this stuff went on

560
00:33:43,560 --> 00:33:46,680
Speaker 3: to become the basis of the invention known as the barometer,

561
00:33:46,800 --> 00:33:50,160
Speaker 3: which is used to detect atmospheric pressure, and for much

562
00:33:50,160 --> 00:33:53,280
Speaker 3: of history, one of the most common liquids used in

563
00:33:53,320 --> 00:33:57,240
Speaker 3: it has been quicksilver or mercury. So people here in

564
00:33:57,240 --> 00:34:00,720
Speaker 3: the seventeenth century had learned a number of things has weight.

565
00:34:00,880 --> 00:34:04,480
Speaker 3: The atmosphere does have weight, and it presses down and

566
00:34:04,520 --> 00:34:08,640
Speaker 3: this affects all different kinds of fluid dynamics in closed containers,

567
00:34:09,160 --> 00:34:13,719
Speaker 3: and at least in an approximate sense, vacuums can be created.

568
00:34:14,320 --> 00:34:16,600
Speaker 3: But the scientific story does not stop there, and maybe

569
00:34:16,640 --> 00:34:18,560
Speaker 3: in the next episode we can get into a little

570
00:34:18,560 --> 00:34:22,799
Speaker 3: more detail on that history, because there's plenty more. But

571
00:34:22,840 --> 00:34:26,000
Speaker 3: also we've got to talk about psychology and horror vacae

572
00:34:26,040 --> 00:34:28,480
Speaker 3: because I don't know about you, but you ever have

573
00:34:28,600 --> 00:34:32,719
Speaker 3: that creepy feeling when you're reminded of like walking around

574
00:34:33,160 --> 00:34:36,440
Speaker 3: at school when there was nobody there, or any other

575
00:34:36,520 --> 00:34:38,920
Speaker 3: place when you were a kid that normally had people

576
00:34:38,960 --> 00:34:40,600
Speaker 3: in it, but then there were no people in it

577
00:34:40,680 --> 00:34:43,000
Speaker 3: and you were there and it just didn't feel right.

578
00:34:43,280 --> 00:34:44,640
Speaker 3: I think about that all the time.

579
00:34:44,960 --> 00:34:47,600
Speaker 1: Yeah, And of course this plays into a lot of

580
00:34:47,600 --> 00:34:49,319
Speaker 1: our horror movies as well, and a lot of our

581
00:34:49,360 --> 00:34:52,680
Speaker 1: fantastic horror scenarios. So we'll discuss some of those. But

582
00:34:53,360 --> 00:34:56,759
Speaker 1: you know, this, coming back to this realization that the

583
00:34:56,800 --> 00:35:03,000
Speaker 1: air has weight, that atmospheric pressure is evolved in these observations.

584
00:35:02,640 --> 00:35:05,640
Speaker 1: It's something that I feel, even as modern humans, we

585
00:35:05,719 --> 00:35:07,839
Speaker 1: have to remind ourselves of this time and time again,

586
00:35:07,880 --> 00:35:10,120
Speaker 1: because we can also fall into that line of thinking

587
00:35:10,160 --> 00:35:12,680
Speaker 1: where we think of an empty room as empty, we

588
00:35:12,719 --> 00:35:16,440
Speaker 1: think of a clear sky as being empty, but of

589
00:35:16,440 --> 00:35:18,279
Speaker 1: course none of those things are empty. All of those

590
00:35:18,280 --> 00:35:22,200
Speaker 1: things are completely filled up with air exerting a pressure

591
00:35:22,239 --> 00:35:24,960
Speaker 1: on us, but a pressure that is so ambient that

592
00:35:25,000 --> 00:35:27,040
Speaker 1: we do not register it as being pressure.

593
00:35:27,440 --> 00:35:30,279
Speaker 3: Absolutely, and the way that this pressure affects other things,

594
00:35:30,280 --> 00:35:33,279
Speaker 3: say like chemical properties. I think about the boiling point

595
00:35:33,280 --> 00:35:36,200
Speaker 3: of water and how that's affected by atmospheric pressure at

596
00:35:36,200 --> 00:35:39,320
Speaker 3: different altitudes, and how that affects something as mundane as cooking.

597
00:35:39,719 --> 00:35:42,480
Speaker 3: How like cooking has to be different at different altitudes.

598
00:35:43,280 --> 00:35:47,279
Speaker 1: Yeah, Ultimately we have to realize that we are creatures

599
00:35:47,800 --> 00:35:53,000
Speaker 1: that evolve to reside within an atmospheric body, and even

600
00:35:53,080 --> 00:35:55,960
Speaker 1: then only certain parts of that atmospheric body. And then

601
00:35:56,000 --> 00:35:58,719
Speaker 1: if we want to bring fire with us and use

602
00:35:58,760 --> 00:36:02,399
Speaker 1: it to boil matter to eat, we have to take

603
00:36:02,440 --> 00:36:04,880
Speaker 1: into account that it's going to boil a little differently

604
00:36:05,080 --> 00:36:09,360
Speaker 1: depending on how far up into that massive body of

605
00:36:09,400 --> 00:36:10,480
Speaker 1: air we travel.

606
00:36:10,840 --> 00:36:13,359
Speaker 3: We discussed this in a couple of episodes a long

607
00:36:13,400 --> 00:36:15,880
Speaker 3: time ago. I think maybe they were the ones about

608
00:36:16,360 --> 00:36:20,840
Speaker 3: sacred experiences on mountaintops people have had. But the fact

609
00:36:20,840 --> 00:36:23,440
Speaker 3: about how you basically like, you can't boil potatoes on

610
00:36:23,480 --> 00:36:26,080
Speaker 3: top of Mount Everest. People have tried. You try to

611
00:36:26,080 --> 00:36:28,200
Speaker 3: boil food to cook it. The problem is the boiling

612
00:36:28,239 --> 00:36:31,399
Speaker 3: point of water after a certain altitude gets too low,

613
00:36:31,840 --> 00:36:34,360
Speaker 3: and so your water is boiling in the pot, but

614
00:36:34,400 --> 00:36:37,520
Speaker 3: it's not hot enough to cook your food, like boiling

615
00:36:37,560 --> 00:36:41,160
Speaker 3: water is no longer sufficiently hot. Well, and of course

616
00:36:41,160 --> 00:36:43,520
Speaker 3: it's boiling. You can't get any hotter than boiling, so

617
00:36:43,640 --> 00:36:45,280
Speaker 3: you're just stuck like it won't cook.

618
00:36:45,760 --> 00:36:47,080
Speaker 1: It's hard to come up with the response to that.

619
00:36:47,120 --> 00:36:51,399
Speaker 1: I'd forgotten about that tidbit regarding cooking potatoes on Mount

620
00:36:51,400 --> 00:36:56,239
Speaker 1: Everest for some reason. That's that's that's that's almost more

621
00:36:56,280 --> 00:37:00,160
Speaker 1: or mind blowing than anything we've we've discussed in this episode. Yes,

622
00:37:00,239 --> 00:37:02,440
Speaker 1: because it comes down to what we were talking about earlier,

623
00:37:02,480 --> 00:37:05,080
Speaker 1: like the perceived world, the world we can relate to,

624
00:37:05,680 --> 00:37:09,719
Speaker 1: versus the world that seems to exist only within the

625
00:37:10,719 --> 00:37:15,640
Speaker 1: lofty conversations of philosophers and scientists. Like the experience of

626
00:37:16,400 --> 00:37:19,879
Speaker 1: boiling potatoes but not being able to cook them through

627
00:37:19,880 --> 00:37:23,000
Speaker 1: that boiling Like that feels like the twilight zone. That

628
00:37:23,040 --> 00:37:24,480
Speaker 1: feels like something that shouldn't be.

629
00:37:24,880 --> 00:37:26,799
Speaker 3: Rod Serling's kind of talking to you about this.

630
00:37:27,239 --> 00:37:29,520
Speaker 1: Yeah, all right, Well we're going to go and close

631
00:37:29,560 --> 00:37:32,200
Speaker 1: this episode out, but we'll be back with more discussions

632
00:37:32,600 --> 00:37:37,239
Speaker 1: of the vacuum, the void, and so forth. In the meantime.

633
00:37:37,880 --> 00:37:40,319
Speaker 1: Right into us, we'd love to hear from everyone out there,

634
00:37:41,360 --> 00:37:43,960
Speaker 1: what are your thoughts about some of the ideas we

635
00:37:44,040 --> 00:37:47,319
Speaker 1: presented in this episode, and hey, we would love to

636
00:37:47,360 --> 00:37:51,680
Speaker 1: hear your cooking anecdotes from different altitudes if you have

637
00:37:52,000 --> 00:37:54,479
Speaker 1: some of those right in. We'd love to hear about

638
00:37:54,480 --> 00:37:57,600
Speaker 1: your mishaps with boiling potatoes and mountaintops. I know we

639
00:37:57,640 --> 00:37:58,879
Speaker 1: have some mountaineers out there.

640
00:37:59,280 --> 00:37:59,799
Speaker 3: Yes, we do.

641
00:38:00,600 --> 00:38:02,840
Speaker 1: Reminder that Stuff to Blow Your Mind is primarily a

642
00:38:02,880 --> 00:38:06,360
Speaker 1: science podcast, with core episodes on Tuesdays and Thursdays. On

643
00:38:06,440 --> 00:38:08,640
Speaker 1: Mondays we do a listener mail episode, on Wednesdays we

644
00:38:08,680 --> 00:38:11,440
Speaker 1: do a short form artifact or monster fact episode, and

645
00:38:11,719 --> 00:38:14,399
Speaker 1: on Fridays we do Weird House Cinema. That's our time

646
00:38:14,440 --> 00:38:16,640
Speaker 1: to set aside most serious concerns and just talk about

647
00:38:16,680 --> 00:38:17,360
Speaker 1: a strange film.

648
00:38:17,800 --> 00:38:21,200
Speaker 3: Huge thanks to our audio producer JJ Posway. If you

649
00:38:21,200 --> 00:38:23,280
Speaker 3: would like to get in touch with us with feedback

650
00:38:23,320 --> 00:38:25,600
Speaker 3: on this episode or any other, to suggest a topic

651
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Speaker 3: for the future, or just to say hello, you can

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Speaker 3: email us at contact at stuff to Blow your Mind

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Speaker 3: dot com.

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Speaker 2: Stuff to Blow Your Mind is production of iHeartRadio. For

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Speaker 2: more podcasts from my Heart Radio, visit the iHeartRadio app,

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Speaker 2: Apple Podcasts, or wherever you're listening to your favorite shows.

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Speaker 2: The art