Dr. Matt Dickerson, a professor of computer science at Middlebury College, recently gave a lecture at MIT on the relationship between physicalism and reason. The lecture was based on the fourth chapter of his book The Mind and the Machine. After developing an account of human identity on physicalism, and developing an account of what a logical reasoning process requires, he concluded that physicalism is unable to support the ability of humans to reason. In this post I will largely build off of his remarks at the lecture.
First, what does physicalism tell us about the human brain? Here is how Richard Dawkins has described the brain:
Like ideally drilled soldiers, computers do what they are told. They slavishly obey whatever instructions are properly delivered in their own programming language. This is how they do useful things like word processing and spreadsheet calculations. But, as an inevitable by-product, they are equally automatic in obeying bad instructions. They have no way of telling whether an instruction will have a good effect or a bad. They simply obey, as soldiers are supposed to.
It is their unquestioning obedience that makes computers vulnerable to infection by viruses and worms. A maliciously designed program that says “Copy me to every name in any address list that you find on this hard disk” will simply be obeyed and then obeyed again by the other computers to which it is sent, in exponential expansion. It is impossible to design a computer that is usefully obedient and at the same time immune to infection.
If I have done my softening up work well, you will already have completed the argument about child brains and religion. Natural selection builds child brains with a tendency to believe whatever their parents and tribal elders tell them. And this very quality automatically makes them vulnerable to infection by mind viruses. For excellent survival reasons, child brains need to trust parents and trust elders whom their parents tell them to trust. An automatic consequence is that the “truster” has no way of distinguishing good advice from bad. The child cannot tell that “If you swim in the river you’ll be eaten by crocodiles” is good advice but “If you don’t sacrifice a goat at the time of the full moon, the crops will fail” is bad advice. They both sound the same. Both are advice from a trusted source, and both are delivered with a solemn earnestness that commands respect and demands obedience.
Under physicalism, everything in the universe is subject to natural laws that operate in perfectly consistent ways. Everything can be explained in terms of cause-and-effect relationships. The human brain cannot, therefore, be a special exception to these principles. The brain is shaped by certain natural laws that govern neurological interactions and is then further influenced by its environment. So, as in Dawkins’ example, we have a naturalistic accounting of the functionality of brain capacity in children, tied to an important feature in their environment – their parents. When you give a full account of both the brain’s capacity and the brain’s environment, as Dawkins has done for children, you can also account for what the brain believes, in this case, religion.
The amount of complexity in the brain doesn’t change this. When the child brain develops into an adult brain, it is equally subject to natural laws and its environment.
The nature of the influence is also irrelevant. In his writings, Dawkins has noted that children are receptive to a dazzling array of religious beliefs. Whether Aztec mythology, Norse gods, the Greek pantheon, Muslim ideology or the Christian faith, Dawkins thinks that it is all nonsense and all spread by an a-rational evolutionary process. What, then, in this framework, separates these belief content structures and the contents of atheism, science, or The God Delusion? The brain accepts any of these belief systems strictly due to the cause-and-effect relationship that governs both its capacities and its environment.
However, Dr. Dickerson pointed out that reasoning requires a categorically different kind of causation: ground-consequent causation. As C.S. Lewis put it,
The cause and effect relation between events and the ground and consequent relation between propositions are distinct. Since English uses because for both, let us here use Because CE for the cause and effect relation (‘This doll always falls on its feet because CE its feet are weighted’), and Because GC for the ground and consequent relation (‘A equals C because GC they both equal B’). . . If an argument is to be verific the conclusion must be related to the premises as consequent to ground, i.e. the conclusion is there because GC certain other propositions are true.
The problem for physicalism is that cause-and-effect relationships are said to govern everything – including the interactions within the brain. But for reasoning to take place, the brain must be the locus of ground-consequent relationships, where statements like, “If P, then Q; P; therefore, Q” can have causal efficacy.
So we find ourselves affirming two contradictory propositions:
- Everything is governed by cause-and-effect.
- Our brains can process and be changed by ground-consequent logical relationships.
To achieve consistency, we must either deny that everything is governed by cause-and-effect, and open our worldviews to something beyond physicalism, or we must deny that our brains are influenced by ground-consequence reasoning, and abandon the idea that we are rational creatures.
Ask yourself: are humans like falling dominoes, entirely subject to natural law, or may we stand up and walk in the direction that reason shows us?
To put it another way: Are you currently using ground-consequent reasoning to assess and respond to this article, or are you subject to deterministic cause-and-effect relationships that are dictating your behavior?