In the 138th episode of “Star Trek: the next generation” I, as a young boy, learned about this quote from Descartes. It may just have been what set me off on my voyage as an atheist since, before that time, the idea that we could question if anything indeed existed, had never occurred to me. It may very well have been my very first metaphysical thinking. This concept is closely related to the question “How come there is something and not nothing?” because if we could question if anything actually existed then perhaps that other question didn’t mean anything. Perhaps all we knew was some kind of ‘nothing’, an illusion and inversely if we were to ask ‘why there was something’ perhaps we first needed to prove that indeed something existed. It is safe to say that I knew nothing then and that I was utterly wrong in my assumed comprehension to what Descartes had meant.
At the time it had seemed logical to me that the fact that we think proved we had to exist. The very complexity of our thinking was so great that it would prevent any simulating algorithm inside a brain (electronic or otherwise) from running all of our thought-processes simultaneously. This was before the current server-farms, supercomputers and artificial intelligence. I don’t remember if Descartes idea was a stimulus to my eagerness to discover mechanics. It is not unreasonable that in a quest to know if reality could be simulated that I ventured from the magical reasoning of a child to the descriptive language of an engineer. There is no real reason to think Descartes was the initial cause to my atheism, but he might have been. Certainly some of you can by now imagine my disillusion when I actually got to learn something about Descartes.
Rene Descartes, a French philosopher published his “Meditationes de prima philosophia, in qua Dei existentia et animae immortalitas demonstratur” in 1641. The work was written in Latin just as its title here. The pain, for those that maintain their Latin, is directly visible in the title. “in qua Dei existential demonstrator”, “..in which the existence of God is demonstrated”. As we will see Descartes used very uncertain concepts to derive certainty from.
Descartes was about the first to critically question the senses and all other ways we employ to obtain knowledge about our world. Unlike Newton however, this realization did not stimulate him to find detection tools that work around our limitations, but rather to fall back on the most basic of certainties and deduce knowledge from there. Also, Descartes’ fundamental doubt about reality does not arise from knowledge about hallucinations or properties of light and sound. He says we must account for the open possibility that perhaps an evil spirit is deluding us in all we know. This is not something we worry much about today.
“So”, said Descartes, “if matter, my body and any information I receive is to be doubted, what can I then still be sure about?” Answer: “I can be sure of that doubt, of the fact that I think.” The reason for this is that “to doubt the fact that you doubt” is a paradox and logically invalid. Next, by definition it is certain that doubt is not something that can exist independent of an actor, so he, the doubter must exist as well. Now while a thinking, bodiless actor Descartes is still not contented. He got one certainty out of the thinking deduction but Descartes is not a nihilist or even a postmodernist, he wants to believe in the existence of everything he sees, he just wants to be justified in doing so.
Digging further for ‘thought-certainties’ Descartes ends up with God. “I”, Descartes said, ‘am a flawed being, evidence being that I doubt and the fact that this doubt is all I can be sure about”. Yet, while being flawed, I can still imagine a ‘Perfect Being’. This cannot be something I created myself by thinking about it because that would require more perfection than I hold. Also we can be sure that this Perfect Being exists for we know that our thinking can prove things that are real and for it not to exist would be imperfect, therefore it must be and we can be sure about it.” God, who according to Descartes is this Perfect Being, subsequently prevents any bad spirit from existing and we can thus be sure that what we see is no illusion at all. We exist, everything we see is real and God is proven as a by-product of our certainty.
I think most readers would not have a hard time coming up with examples of their own that suggest Descartes went wrong. Most examples would include imagining some object with certain properties which would be destroyed if the object was just imaginary. Unfortunately these would be poor counter arguments since Descartes argument works for little else except a perfect divine being. Still the argument seems rather naïve or circular and gives us a bad impression about the intelligence of both Rene and his contemporary intellectuals. Given that the mathematician Christiaan Huygens published on mathematical approaches to time-measurement and navigation across earths longitudes some twenty years later, we should certainly not be too smug about this. I for one could not have done this. Descartes reasoning must instead be seen as a symptom of the entrenchment of religious views into the intellectual world.
As it stands it is not with withy examples that we will disprove Rene. His logic is not entirely circular either. The fallacy it is based upon is a mistaken premise: “I can imagine a perfect being”. On the face of it this seems easily enough to do. The mistake is that we take a representation of something, a thought about it, to encompass its entire reality. We think of God as perfect, being imaginary is not perfect so therefore he must exist. But perfection is not something we can imagine in more than an abstract sense. It is loaded with contradictions the mind cannot imagine at all. Can a perfect being not create a stone it cannot lift? A perfect divine being with infinite properties would be able to both make a rock it cannot lift as well as lift it. This is a paradox equal or greater than ‘doubting your own doubt’. In fact it turns out we can’t imagine a perfect being at all, let alone make it of greater perfection than the mind imagining it or owning a property that self-defines its existence.
Furthermore the original paradox that proved to Descartes he existed, “I cannot doubt my doubt’ is not real. To doubt your doubt is having a thought about a thought where the content of the second thought says something about first. It only becomes paradoxical when the second doubt in indirectly saying something about itself, but it is not. They are separate thoughts. And even if they weren’t; suppose you had a thought “Al my thoughts are planted into my brain and aren’t really mine.” Which would suggest this thought was also implanted. Whether this is so or isn’t can’t be determined by the thought. Even a thought “All my thoughts are wrong” isn’t ultimately paradoxical since this single thought can be wrong independently from all the others as soon as one other thought is not wrong. It also can be almost right when most but not all thoughts are wrong.
The actual problem which Descartes is referring to is whether a system can contain itself and therefore simulate itself. Could my mind understand itself in such a way as to envelop itself entirely? This idea seems absurd at hand but it was a real problem for Descartes. If this could be done our consciousness could be a hallucination of itself. Remember how Descartes excluded the possibility that God was a figment of our imagination by stating God was too big/too perfect to be hallucinated. By the same way our thinking cannot be enveloped by our own thinking since -to record the position of every electron in our brains- would require actions that moved electrons to other places.
In 1931 Kurt Gödel proved that axiomatic mathematical systems could not prove within themselves that every true statement could be proven true and also proved that it wasn’t impossible to have wrong statements or paradoxes which could not be proven wrong internally. This incompleteness theorem prevents a mathematical system from encompassing itself and so assuring there would never be any paradoxes. I think it is safe to say it is a mathematical proof that prevents a knowledge system from containing itself as well.
By this proof Descartes is half correct; some demon cannot delude us into imagining our thinking (which is not to say that he can’t simulate it on a computer bigger than our consciousness). At least it is certain that our doubt must exist in some external reality, whether this is the material world or whether it is simulated alongside that reality on a giant calculator or holodeck. We think, therefore we are.
Now this seems all to be an argument for the theist-side of things. If we can be simulated on a computer it must mean God is not a DJ but a software engineer who writes perfect software in six days time. Or God could also be the computer we are all running on. Or God could just be the code we are written in. If we say that God = nature = the ‘laws of physics’ you’d probably end up with an undeniable statement. But defined like this, God is a hollow concept since none of the dogma’s of any of earths religions would apply to him. He wouldn’t be an intelligent designer at all. If God was the ‘IT-guy’ by contrast we’d have to wonder about the room he was working in and who build the computer, never mind who build himself.
Creationist love the notion of ‘irreducible complexity’. In a scientific mathematical sense it just means a system cannot be described in a shorter way. Take for instance the law of motion. Any acceleration can be abbreviated to an equation of mass, force and friction. Beyond that it cannot be reduced without losing the power to describe the system. Since quantum-mechanics and the Heisenberg’s uncertainty principle we have come to regard many aspects of reality as ‘irreducible complex’. If reality was a film and we rewind it before playing it again, it would not necessarily play out the same way. There is no code that can describe reality in a reduced way and the same can probably be said of our thought processes. The physics behind it can be deterministic, but thanks to uncertainty, we cannot predict what we’ll think or decide before we actually do it and, were we to rewind time, the second time around we might decide something else entirely.
With the Higgs boson identified we increasingly live in a universe were reality is not so much made from ‘stuff’ as much as that everything is made from mathematical objects with certain properties that result from objects’ relations with each other. This is basically what theoretical physicist Max Tegmark thinks. In such a mathematical universe it is entirely logic to think it is all calculated. But none of it would work with a simpler model of itself. To know what is going to come next you just may not have another option but to wait and see how reality unfolds. If reality is so irreducibly complex, it seems hard to imagine that it was simulated at all. If thinking is so irreducibly complex, it seems hard to imagine that it was simulated. Thus it seems difficult to maintain we are just simulations. Reality may actually be real. We think, therefore we very well might just bloody well exist.