Wednesday, April 12, 2023

A story about sunlight on a stone

 Suppose that a snail is crossing the garden. It goes across a stone that has been heated by the sun.

Snails have cerebral ganglia with myriad neurons — too many to count, as the ancient Greeks would say, tens of thousands.

We humans, who have brains with billions of neurons, don’t know what it’s like to operate with a snail’s cognitive capabilities. But we say that the snail, using its senses, is aware that the stone is hot. Perhaps that’s why the snail is taking a detour.

That is about the extent of the explanatory power of our scientific worldview on the topics of cognition and consciousness.

We have a lot of descriptive information. We have learned about the structures of the brain and their functions. We know a lot about the development of the human brain in childhood. We know about the brains of other animals and can describe their various capacities for reasoning, including their capacity to use tools.

But if we are asked to explain why nature has produced species with such varying capacities for cognitive behavior, evolutionary theory doesn’t take us much past the story of the snail.

We can understand why it would be an advantage for an organism to sense heat.

But why would evolution produce an organism that notices not just that the stone is hot but that it is sunlight that heats the stone? Or one that further notices that every time the sun is shining that the light heats the stone and reasons from subjective perceptions to the universal law of nature that the sun is the cause of the heat?

The example — minus the snail and the dismay about the state of the Western scientific worldview — comes from Immanuel Kant. In 1783, he used the example of the sun heating a stone to show the rational steps necessary to derive a natural law from sense perceptions.

In terms of how this is possible biologically, I think evolutionary theory explains the snail and a little more.

It doesn’t get us anywhere near Kant’s neighborhood.

• Source: Immanuel Kant, Prolegomena to Any Future Metaphysics; Indianapolis: The Bobbs-Merrill Company, Inc., 1950, pp. 49n, 59.

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