Einsteinian Relativity


“Einstein proposed two things, really quite innocuous when you hear them. One is that, just like on a train, if you’re sitting on a train at the station you momentarily kind of nod off, you wake up and the only thing you can see is another train next to you and it’s moving with respect to you, and in that split second, you can’t tell whether you’re moving or whether it’s the train next to you, and it’s the idea that, well actually, all you can say is “I’m moving relative to something else”. So that was the first idea, that saying that actually, all the laws of physics are the same no matter how you’re moving, it’s the same, there’s no particular special speed or reference in the universe.

In other words, I mean that’s how, you know an air hostess can serve coffee on a plane, she doesn’t have to correct for the speed of the plane, she just pours the coffee, because the laws of physics are exactly the same. So that’s the first idea. That’s not so hard to swallow.

The second idea is slightly harder, and that is the idea that – which again we go by experiment – is the idea that unlike any… anything else, speed of light is constant for whoever observes it, and it’s the same value. So okay let me just explain what that means. I mean, normally if you’re… you know if somebody throws a cricket ball at you, and you’re stationary, you feel a certain hit in your hands as you’re…. as it hits you. If you’re running away from it, the cricket ball reaches you at an actually slower relative speed, so it hurts less when you catch it. If you run away faster than the cricket ball – I personally can’t do that – but if you did, the cricket ball would never… it wouldn’t actually catch up with you. So in that sense, the cricket ball is….. changes it’s speed relative to what you’re actually doing.

Now light doesn’t do that, it doesn’t matter how fast you run, you will always measure the speed of light to be exactly the same. Now how on Earth did Einstein arrive at this conclusion? What he did, he – so the story goes – he imagined himself looking into a mirror, as he approached, and going faster and faster trying to catch up with light. What would the image in the mirror look like? Because if light is like the cricket ball, of course, if he’s going at the speed of light, the light will never actually leave his face, hit the mirror and get back to him, so his image will actually disappear.

But we’ve already said that well, there’s no special… there’s no way of telling whether you are moving or somebody else is moving, so if his image disappeared, he would be able to tell that he was moving and that somebody else wouldn’t. He’d just make a telephone call back and say “Well my image has disappeared”, and that breaks then, the first postulate, it goes against the first one. So combine those two things together, and suddenly all…. you know the heavens open, the notions of time change.”

– Neil Johnson, In Our Time (Programme 54) “Time”

Indeterminacy in Nature


“[…] we’re talking really about things that started 100 years ago. These effects of relativity, that Einstein is so famous for, are one side of things. But of course, he won his Nobel prize for something completely different, which was something to do with quantum physics, which is not related, it maybe related in the future, but it’s not related immediately to the very long times that we’re talking about for cosmological properties, it’s related to very, very short times, related to what electrons do inside atoms, and of course, eventually what things do inside the nucleus of the atom, but let’s just keep it on the scale of, you know, we’re made of atoms, everything is made of atoms, these atoms contain negative charges called electrons and they zip around all over the place very very fast, but they don’t zip around like billiard balls or cricket balls, they’re actually…. they live in this very strange, kind of undecided world of being partly a particle and partly a wave.

This, actually was something that, as I said, Einstein won the Nobel prize for it, but didn’t like, in some sense the monster he created, because he couldn’t… he didn’t accept this indeterminacy at a fundamental level in nature.”

– Neil Johnson, In Our Time (Programme 54) “Time”

Chinese Room Argument


“Now what I imagine is, take some cognitive capacity that I don’t have. I don’t speak Chinese. So you just imagine that I am locked in a room full of boxes of Chinese symbols and I have a rule book called a computer program, and I get symbols in, in the form of questions, I look up what I’m supposed to do in the rule book, I follow the program and I give symbols back in the form of answers.

Now, on the outside of the room, anybody would say, “well that guy understands Chinese, because, look, we ask him the questions and he gives the answers”. But the point is, and I don’t have any doubt about this, I don’t understand a word of Chinese – and this is the point of the parable – since no computer program, no computer implementing a program has anything that I don’t have, then if I don’t understand Chinese on the basis of implementing a program, neither does any other digital computer on that basis. So the idea that you can produce the understanding just by running a computer program, that that’s enough, that’s wrong.”

– John Searle, In Our Time (Programme 29) “Artificial Intelligence”

Newtonian Time


“It’s really a clock in the sky for all to see. Very much like in the birth of the railroad, when there was one clock in the centre of the station which set the time for the town in which the station was. It was a universal time. The Newton idea is that there is a clock in the sky for everybody in the universe to see. Everybody agrees on that time, no matter how far they are away, and no matter how…. what they are doing at a particular moment, when they look at the clock. […]

In terms of how bodies and objects moved through time, that was of course a mystery until Newton came along. People weren’t sure when they looked up at the sky whether the planets moved by themselves or there was some big hand behind, trying…. moving them along and while they were asleep it would put the sun down and put the moon up and bring the sun back the next day, and of course, what Newton did was show that actually objects did move in a very precise way, as this thing called “time” progressed.”

– Neil Johnson, In Our Time (Programme 54) “Time”

Consciousness of a Bat


“There’s a brilliant paper by Thomas Nagel, which asks “what’s it like to be a bat?”, and this is the third person experience which he points very clearly to – you cannot have a scientific approach to – but what science does in very simple terms, is to work out what a bat needs to have in order to know it’s a bat. We are never going to know! But how do we know that that bat has the right circuitry to know anything? And I think that is a scientific question, and perhaps it’s an important one. […]

A bat knows it’s a bat enough to survive as a bat, and that may be very little, in comparison to the sort of things we have to know to survive with our complexity.”

– Igor Alexander, In Our Time (Programme 76) “Science of Consciousness”