Descartes’ zero-axiom system
I first properly encountered Descartes in European History class, where he was introduced as the great skeptic who had rejected everything he believed, leaving only the essential, irrefutable, true-in-all-conceivable-universes “I think, therefore I am” – cogito ergo sum. Magnificent.
I had always meant to read some Cartesian philosophy, but I guess it slipped my mind. Except that this system of assuming nothing kept coming up. Douglas Adams references it in The Hitchhiker’s Guide to the Galaxy with Deep Thought, the super-computer which had been fed “I think therefore I am” and had deduced the existence of rice pudding and income tax in a blink of an eye.
Descartes’ fear of an “infinitely powerful demon” which sought to deceive mankind and which could only be defeated or circumvented by the “natural light of reason” is also referenced frequently in other writing, although less than respectfully.
And there’s a good reason for this. My history book said that Descartes used his self-verification and “deduced, by systematic reasoning, the existence of God and much else.” Just like Adams’ Deep Thought, right?
Nope. I read into some of his philosophy, and it seems to be caught up in self-verifying truths, without any sort of actual direction. His ontological argument is frightfully convoluted, basically stating that the fact that we can conceive of an all-powerful being necessitates the existence of one, since the thought has to come from somewhere. His mind-body dualism is basically wrong as well, although it can be construed as correct, since ideas can be treated as abstract entities (although thanks to neuroscience, it is very clear that they originate from neurons). So Descartes is endlessly bogged down by tautologies, such as “I can think, so therefore it is my essence to think” and so on.
However, although his powerful-demon argument is flawed, it does hold some relevance today because of the computer-simulation theory of existence – the idea that it is supposedly extremely likely that we live not in a physical world but in a computer simulation. But it should be clear that the only way to actually verify this is if there was some sort of logical inconsistency. By the “natural light of reason,” it would be impossible to conceive of a real world in which there is some sort of contradiction. So if this demon of ours was inconsistent and pi equaled 3.14195… in Los Angeles but 3.15 in New York, then wouldn’t we be able to point to a jarring inconsistency in our world, and start to wonder what was up? The demon would have been lazy and not all-powerful. Similarly, if we were to be living in a computer simulation, and one day the software which generates landscapes from a database got switched out with a random landscape-generator, we would notice, right? Our evening walks would suddenly look totally different every single day.
So I guess my point is this: if we accept zero axioms, assume literally nothing, as Descartes does, then there’s nothing we can do except stay grounded in self-verification. Perhaps, in a sense, we cannot trust our own senses. Maybe there is a demon up there somewhere, who’s now laughing at us because we think that the sky is blue and not pink. What’s the implication? Maybe we can’t trust our senses exactly, but at least we can imagine them to be consistent. And if that were to fail somehow (I start to see the sky as green on some days) then at least I have my ability to reason to fall back upon to see what is going on.
So, the moral of the story: I can’t sit in a cottage in the middle of the forest and deduce the nature of the universe. The universe exists in a certain way that is necessarily consistent, but cannot necessarily be deduced without actually looking at it. Similarly, we can have lots of different formal systems which are different from each other but still consistent under some model. To understand the universe, I need to go out and experiment with it and test hypotheses, and also create an axiomatic system of reasoning with certain assumptions other than the ones are self-verifying. It doesn’t seem possible to create a world which is both inconsistent AND impossible to verify for its inconsistency. So Descartes, instead of being afraid of whether there’s an infinitely powerful demon deceiving your sensory perception, go out and find out how everything works. If the infinitely powerful demon has created a consistent world for us to live in, we will never ever have any chance of finding out, so why should it matter?
If anyone has any good reading material on this particular topic, I would very much appreciate if you could post it/send it to me. Thanks.