Alvin Plantinga and The Matrix

The student newspaper on campus recently had a point/counterpoint between me and a philosophy professor, Dr. Brian Lang, regarding evolution. He summarized an argument by Alvin Plantinga. I gave a response in the newspaper, but here I would like to focus on another aspect that I did not have space to discuss in my first response.

The basic argument is below:

The general conclusion of Plantinga’s argument is that belief in current evolutionary doctrine is self-defeating. In order to show how this is the case he differentiates between true beliefs and beliefs with survival value. It is possible that there is some overlap between these types of beliefs. That is, sometimes believing the truth better equips a creature to survive. But this need not always be the case. ….

Plantinga’s critique focuses on one specific implication of modern evolutionary doctrine. That is, if humans have evolved by natural selection over a long period of time then our minds have been fine-tuned to produce false beliefs with higher survival value over and against true beliefs with lower survival value. This is because creatures that held true beliefs with lower survival value would have tended to propagate less. … Therefore evolution gives humans a reason to think that our belief-forming mechanisms (brains, eyes, etc.) are generally useful for survival rather than that they are truthful. This includes when our brains tell us that the theory of evolution is true. So we have the interesting consequence that if evolution is true, then we have a powerful reason to comprehensively distrust our brains—including when our brains inform us that evolution seems to be true!

… The standard response is for scientists to point out that true beliefs typically have high survival value. For example, having eyes that tell you the truth allows you to avoid falling off cliffs, going near predators, etc. The problem with this response is that evolution undermines our trust in all of our beliefs—including this one. The fact that it appears that having trustworthy beliefs would have great survival value is itself a belief produced by our brains. …. By accepting the evolutionary premise that our minds have developed under conditions that favor survival over truth, evolutionists have undermined their own ability to trust their thoughts about anything—including any rebuttal they might put forward against Plantinga.

In my response here, I do not want to focus on the biology of the argument as I did in my first response. Instead, I would like to point out that this argument is self defeating and in fact is a critique of the possibility of any knowledge.

Plantinga’s argument is unfalsifiable as presented, since any argument to show that evolution can produce true belief could itself be the product of our defective brain. However, this circular and unfalsifiable position is not restricted to a brain derived by natural selection. As is typical of anti-evolution arguments, no alternative explanation is offered.

The emptiness of this argument becomes apparent when you realize that it would also apply to a world like the Matrix. In the move The Matrix, the world we experience isn’t real. It’s a virtual reality created by machines as our bodies sit in vats. A person in the Matrix could come up with all sorts of arguments to show that his or her brain and senses are reliable, but all of these arguments fail because the very brain and senses we are using are what is in dispute. According to Plantinga, if evolution is true, we live in a Matrix-like world, where we can never trust what our brains tell us because our brains are systematically biased.

There is no way for me or anyone to positively prove that they do not live in the Matrix. There is no way to prove there is an external reality at all. However, everyone lives there lives as if there is an external reality and the world is real. Regardless of what they profess, no one really believes we live in the Matrix, and there are no true solipsists. It is reasonable to live your life as if the world exists unless something suggests otherwise. In the same way, it is reasonable to assume our senses are a reflection of reality unless something suggests otherwise (and we do know of some specific ways in which our senses are not accurate). If Morpheus starts to speak to me through my computer and a white rabbit shows up at my door I might change my mind about living in the Matrix, but until then, I won’t waste my time on self defeating naval gazing.

Any alternative explanation for the origin of our brains will suffer from the same problem. Perhaps God gave us our brain. But how do we know He gave us a reliable brain? Martin Luther said that reason is the devil’s whore, so he clearly did not believe our brain is a reliable tool. Or perhaps God gave us a brain that is only useful for survival and not for finding truth, just like selection. There is no a priori reason to think otherwise. I would challenge someone who follows Plantinga’s argument to prove that their brain is reliable in a way that doesn't fall victim to the same unfalsifiable Matrix world. Just the possibility that our brains are wired for anything other than truth, for any reason, will undermined our ability to trust our thoughts about anything—including any rebuttal we might put forward against this deceptive God.

I will address Plantinga’s another aspect of Plantinga’s case in a later post.