CS Lewis on Brains

Here I respond to C.S. Lewis and his twisted logic where he concludes that atheists can’t trust their brains.

[Key Takeaway]

You can trust you brain to work because survival has made it a requirement. The brains that did not work, led to death and were weeded out long ago. This is a much stronger reason to believe that brains function, than merely thinking that some entity "made them work".

Quote

C.S. Lewis is quoted saying (the sentence numbers are added by me)

1. Supposing there was no intelligence behind the universe, no creative mind.
2. In that case, nobody designed my brain for the purpose of thinking.
3. It is merely that when the atoms inside my skull happen for physical or chemical reasons to arrange themselves in a certain way, this gives me, as a by-product, the sensation I call thought.
4. But if so, how can I trust my own thinking to be true?
5. It’s like upsetting a milk jug and hoping that the way the splashes arranges itself will give you a map of London.
6. But if I can’t trust my own thinking, of course I can’t trust the arguments leading to atheism, and therefore have no reason to be an atheist, or anything else.
7. Unless I believe in God, I can’t believe in thought: so I can never use thought to disbelieve in God.

Natural Brains

“nobody designed my brain for the purpose of thinking”

Here we see the fundamental underlying bias that Lewis holds: that intelligence is required to create intelligence.  A “thinking brain” must be designed by another thinking being.  He simply does not understand how intelligence evolved.

Intelligence evolved due to the need to survive.  Imagine it this way: millions upon millions of different versions of the brain were created at points in time, some of them more intelligent than others.  Obviously, the more intelligent ones were selected.  Why?  Because they had a more accurate picture of the world around them, and that allowed them to more accurately respond to what was going on.

Some brains had thoughts, and some didn’t.  And you know what?  The ones that could think did better, survived longer, and passed more of their genes along.  Is this really that hard to understand?  Understanding the world around you is a HUGE advantage when it comes to competition and survival.

The best way to design a brain, would be to make millions and millions of brains, put them in competition with each other, and find out which one does the best thinking by seeing which one survives the best in a challenging environment.

Unreliable Brains

For evolution to fail to produce brains that think, Lewis would have you believe that

• brains that could not think did just as well as thinking brains
• brains with a poor understanding for the world did just as well as the brains with a good understanding of the world
• brains with poor awareness of the world did just as well as brains with a good awareness of the world

It is mind blowing that he thinks there is no benefit to thinking in the game of survival.  it is just crazy to think that there is absolutely no evolutionary pressure to have good thinking and good understanding of the world.  To believe that non-thinking animals could perform as well a thinking animals means that Lewis has a very poor opinion of thinking in general.  Of course evolution will select for better thinking, better understanding, and more reliable brains.

Atoms and Chemicals

“when the atoms inside my skull happen for physical or chemical reasons to arrange themselves in a certain way, this gives me, as a by-product, the sensation I call thought”

Yes, now that you mention it, to have a particular thought, the atoms must be arranged to make that happen.  That is how thinking works.  How does Lewis think it works?   It is a physical process in the nervous system, and not a magical free-floating entity from another realm.

Lewis here is making the arrogant assumption that arrangements of atoms can not produce thoughts.  He is not a neurologist and can not speak knowledgeably about how thoughts occur.  This is argument by incredulity: he just can’t imagine molecules interacting to produce thought, so he sneers at it.

Trust Proven by Evolution

“how can I trust my own thinking to be true?”

The reason that most humans can trust that their thinking is effective is that a brain of this form has kept them alive for millions of years.

Imagine that a creature could not trust its brain.  For example, when being attacked from the left, the animal thought it was from the right.  Even a lowly gazelle has to have a brain that accurately represents the true world — so it can effectively run away.  Any animal with a brain that could not be trusted would have been eaten long before it could pass on genes.

So yes, humans can trust the brain because the current form was the one that won all the competitions for the last million years.  Evolution will retain in the gene pool the most trustworthy brains.  That is why you can trust it.

I must say, however, a brain that had been designed by intelligence would not necessarily be trustworthy.  Just because a programmer makes a self-driving car, does NOT mean that you can trust that car to drive perfectly.  Programmers can and will make mistakes.  A brain designed by an intelligence is not proven in the way that evolution does with millions of generations.

Straw Man Argument

“It’s like upsetting a milk jug and hoping that the way the splashes arranges itself will give you a map of London.”

No, it is not like that at all.  Millions of generations of animals lives and died.  And only the ones with the most effective brains survived.

Maybe he is trying to argue here that the brain had to suddenly appear in final form?  That is a standard logical flaw that apologists use to confuse people.  Obviously the milk jug happens only once, and not millions of times in succession.  And each succession brings the genes from prior successful cases.

C.S. Lewis was not stupid, and he must have known at least the basics about evolution.  For him to compare the long process of evolution to a single event like spilling a milk jug, is dishonest at multiple levels.

Special Pleading

“if I can’t trust my own thinking, of course I can’t trust the arguments leading to atheism”

You can trust a brain that proved itself with evolution, but you certainly can not trust a brain that was put together by “intelligence”.  We can only trust our brains because they have they have been “proven” by evolution.

Lewis will argue his opinion that God must be perfect in everything, so if a brain was created by god it would be perfect in every way (never mind all the varieties of mental illness we know of).  This “god is perfect because god is perfect” argument is just Special Pleading

Illogical Conclusions

“Unless I believe in God, I can’t believe in thought”

Lewis’ motivated reasoning has brought him around to his final conclusion: believe in God or else.   He apparently did not understand how evolution works, and would in fact produce a more trustworthy brain.

The preceding logic is faulty, so the conclusion is similarly faulty.  The flaw was in Lewis’ assumptions at the beginnings: evolution would produce unthinking and unreliable brains.  He has no evidence for this, but really just argument from incredulity.  He doesn’t know how it works, so God must have done it.