Wednesday, April 8, 2020

What if my kidney got smart?

Suppose the cells in my left kidney mutated, and the kidney grew neurons and started engaging in the same sorts of computations that my brain consciously does. (The idea is not as outlandish as it may seem. We will no doubt one day be able to make replacement kidneys in the lab. And if so, why not replacement kidneys with neurons?)

Question: Would I come to have a new mode of kidney-based consciousness on top of my brain-based consciousness?

I don’t know the answer to this as a genuine hypothetical question. But I have a strong intuition that there is no metaphysical guarantee that I would have a new mode of kidney-based consciousness. The mere fact that my kidney functions computationally like a brain doesn’t guarantee that I think with it.

It’s an interesting question which views about persons and mind can agree that there is no guarantee of my consciousness through kidneys.

Brainists, who think that we are brains, will happily agree. I think with my brain because I am my brain. The kidney would, perhaps, think, but it wouldn’t be me thinking, because the kidney isn’t even a part of me.

Dualists of all sorts can agree: for there is no guarantee that kidney-based computation gives rise to consciousness, since the connection between neural function and mental function on dualism can be contingent.

Some non-dualist animalists, however, will have a problem. For a non-dualist animalist will identify us with the animal, and then many of them will presumably want to say that the animal thinks provided that it has an organ that engages in certain kinds of neural behavior. But now it seems like I would have to be thinking through the kidney if it were to engage in this neural behavior.

But it’s not quite so simple. For it could be that the neural behavior that defines thought has a normative component. Thus, to think may require the neurons to appropriately engage in certain behaviors. But neurons in the kidney would not have proper function.

Thus, perhaps, the no-guarantee constraint only rules out one of the views I’ve considered: non-normative non-dualist animalism.


Atno said...

If I understand that last part correctly, the idea would be that there would have to be some kind of proper function (which could be supplied by a Form) for us to think. Neurons in the brain would appropriately engage in certain behaviors, but neurons in the kidney would not.

But the suggestion that this is the whole story is incredibly implausible to me. It reminds me of Rasmussen's point about how different movements or arrangements of dust are completely irrelevant for bringing about consciousness or any other mental states. The idea that if only the kidney-neurons started appropriately moving in the proper behavior they would then start thinking is crazy to me. Intelligence is a perfection, as Samuel Clarke would put it, and the Form must have the perfection in itself; it can't just be a matter of rearranging movements or making the same substance operate in a "proper" manner.

Martin Cooke said...

Yet another nice argument, Alex. I see nothing wrong with it, but your "to think may require the neurons to appropriately engage in certain behaviors" makes me wonder what you would say about a split-brain hypothetical in which a brain was split into two functioning halves. Would you say that such an operation was impossible?

David Duffy said...

We know the effects of sensory deprivation on brain development - so what inputs does this new brain receive?

Alexander R Pruss said...

Maybe it gets inputs regarding the chemistry of the waste products in the body.