HARRIS: It’s worth emphasizing the connection between perception and action. It’s one thing to talk about it in the context of catching a cricket bal… - Sam Harris

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HARRIS: It’s worth emphasizing the connection between perception and action. It’s one thing to talk about it in the context of catching a cricket ball, but when you talk about the evolutionary logic of having developed perceptual capacities in the first place, the link to action becomes even more explicit. We haven’t evolved to perceive the world as it is for some abstract epistemological reason. We’ve evolved to perceive what’s biologically useful. And what’s biologically useful is always connected — at least when we’re talking about the outside world — to actions. If you can’t move, if you can’t act in any way, there would have been very little reason to evolve a capacity for sight, for instance.
SETH: Absolutely. The sea squirt — a very simple marine creature — swims about during its juvenile phase looking for a place to settle, and once it settles and starts filter feeding, it digests its own brain, because it no longer has any need for perceptual or motor competence. This is often used as an unkind analogy for getting tenure in academia. But you’re absolutely right: perception is not about figuring out what’s really there. We perceive the world as it’s useful for us to do so.
This is particularly important when we think about perception of the internal state of the body, which we mentioned earlier. Brains are not for perceiving the world as it is. They didn’t evolve for doing philosophy or complex language, they evolved to guide action. But even more fundamentally, brains evolved to keep themselves and their bodies alive. The most basic cycle of perception and action doesn’t involve the outside world or the exterior surfaces of the body at all. It’s all about regulating the internal physiology of the body and keeping it within bounds compatible with survival. This gives us a clue about why experiences of mood and emotion, and the basic experiences of selfhood, have a fundamentally nonobject-like character.