A few years back I caught up with someone I went to school with, whom I hadn’t seen in decades, and, as it happened, had studied civil engineering like me. I told him I had a philosophy blog where I wrote about science and mathematics, among other things. He made the observation that mathematics and philosophy surely couldn’t be further apart. I pointed out that in Western culture they had a common origin, despite a detour into Islam, where mathematics gained a healthy and pivotal influence from India.
I was reminded of this brief exchange when I watched this Numberphile video on the subject of numbers, where Prof Edward Frankel (UC Berkeley) briefly mentions the role of free will in our interaction with mathematics.
But the main contention of the video is that numbers do not necessarily have the status that we give them in considering reality. In fact, this is probably the most philosophical video I’ve seen on mathematics, even though Frankel is not specifically discussing the philosophy of mathematics.
He starts off by addressing the question whether our brain processes are all zeros and ones like a computer, and obviously thinks not. He continues that in another video, which I might return to later. The crux of this video is an in-depth demonstration of how a vector can be represented by a pair of numbers. He points out that the numbers are dependent on the co-ordinate system one uses, which is where ‘free will’ enters the discussion, because someone ‘chooses’ the co-ordinate system. He treats the vector as if it’s an entity unto itself, which he says ‘doesn’t care what co-ordinates you choose’. Brady, who is recording the video, takes him up on this point: that he’s effectively personifying the vector. Frankel acknowledges this, saying that it’s an ‘abstraction within an abstraction.’
Now, Einstein used vectors in his general theory of relativity, and one of the most important points was that the vectors are independent of the co-ordinate system. So we have this relationship between a mathematical abstraction and physical reality. People often talk about mistaking the ‘map for the terrain’ and Frankel uses a different metaphor where he says, ‘don’t confuse the menu for the meal’. I agree with all this to a point.
My own view is that there are 2 aspects of mathematics that are conflated. There is the language of mathematics, which includes the numbers and the operations we use, and which are ‘invented’ by humans. Then there are the relationships, which this language describes, but which are not prescribed by us. There is a sense that mathematics takes on a life of its own, which is why Frankel can talk about a vector as if it has an independent existence to him. Then there is Einstein who incorporated vectors into his mathematical formulation to describe how gravity is related to spacetime.
Now here’s the thing: the relationship between gravity and spacetime still exists without humans to discover it or describe it. Spacetime is the 3 dimensions of space and 1 of time that, along with gravity, allows planets to maintain orbits over millions of years. But here’s the other thing: without mathematics, we would never know that or be able to describe it. It’s why some claim that mathematics is the language of nature. Whether Frankel agrees or not, I don’t know.
In the second video, Brady asks Frankel if he thinks he’s above mathematics, which makes him laugh. What Frankel argues is that there are inner emotional states, like ‘falling in love’, which can’t be described by mathematics. I know that some people would argue that falling in love is a result of biochemical algorithms, nevertheless I agree with Frankel. You can construct a computer model of a hurricane but it doesn’t mean that it becomes one. And it’s the same with the brain. You might, as someone aspired to do, create a computer model of a human brain, but that doesn’t mean it would think like one.
This all brings me back to Penrose’s 3 worlds philosophy of the mathematical, the mental and the physical and their intrinsic relationships. In a very real way, numbers allow us to comprehend the physical world, but it is not made of numbers as such. Numbers are the basis of the language we use to access mathematics, because I believe that’s what we do. I’ve pointed out before, that equations that describe the physical world (like Einstein’s) have no meaning outside the Universe, because they talk about physical entities like space and time and energy – things we can measure, in effect.
On the other hand, there are mathematical relationships, like Riemann’s hypothesis, for example, that deals with an infinity of primes, which literally can’t be contained by the Universe, by definition. At the end of the 2ndvideo, Frankel quickly mentions Godel’s Incompleteness Theorem, which he describes in a nutshell by saying that there are truths in mathematics that can’t be formally proven. So there is a limit on what the human mind can know, given a finite universe, yet the human mind is 'not a mathematical machine’, as he so strongly argues.
He discusses more than I’ve covered, like his contention that our fixation with the rational is ‘irrational’, and there is no proof for the existence or non-existence of God. So, truly philosophical.
2 comments:
Twice I thought I was above numbers. Then I remembered the irrationals and the complex numbers.
I don't know how familiar you are with Cantor and Turing, or for that matter, Gregory Chaitin (who is contemporary), but there are infinitely more 'uncomputable' Real numbers than 'computable' Reals, which suggests that most of mathematics is not accessible by logic. I'd recommend Chaitin's book, Thinking about Godel and Turing.
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