I Sense, Therefore I Think

One of the most amazing things about human consciousness is that we experience it as a holistic unified experience. As we interact with the world we see, hear, and smell. We remember. We feel. We think. It’s this seamless unification that makes us forget sometimes that all these processes that contribute to our conscious experience are actually separate and distinct processes in the brain. One of these days I’ll try to tackle the question of how these processes become unified, but today I want to explore a somewhat simpler question. What is the relationship between the senses and consciousness? Can you even have consciousness without sensory experience? This is a deceptively difficult question, so let’s start simply and take a short walk through a little thought experiment.

If we took away any one of our senses, while this would drastically alter the nature of our conscious experience, it wouldn’t in any way remove our conscious experience. Blind people and deaf people are still conscious. This seems so obviously true that you might wonder why I even mention it, but we have to start somewhere. Let’s move on and make this more complicated.

What if we take away ALL your senses? Imagine that you couldn’t see, hear, smell, taste, or feel anything. Not very easy to do, is it? And it shouldn’t be, because without our sensory systems transferring stimuli from the world outside our bodies, there would be nothing for our brains to integrate to create our conscious experience. But the difficulty in imagining this state of being isn’t the same as saying that there wouldn’t be anything that it’s like to be in that state being. You would still have your thoughts and memories and the lack of an external world couldn’t take that away from you. The underlying nature of this state of consciousness would certainly be mysterious to us. How would you know if you were dreaming or awake? Would you be living in a perpetual dream state? Would you even feel the passage of time? It’s arguably impossible for us to speculate on what this existence would be like, but I feel pretty confident in stating that it would be like something.

And so while the questions about this senseless state of existence are many, few would deny the label of consciousness to one in this predicament. But we still haven’t been true to the original question we asked ourselves so far. Because for those thoughts and memories to exist in your sensory free consciousness, depends on a history of having intact sensory experiences to be able to interact with the world and develop memories and a thought process. Had you been born without a single functioning sense organ, there would never have been a chance for you realize your potentiality for consciousness. Think about a baby born without any senses whatsoever. What would be going on in its head? What could ever go on in its head? So while this potentiality for consciousness is innate to humans it is only through experience that this potentiality can be realized, and it is only through our sense organs that experience is possible. Without a means of interacting with the world around us, there is nothing available for us to think about. This “aboutness”, this intentionality towards the world is the mark of consciousness. So while Descartes was right (I think, therefore I am), let us not forget that to think, I must first sense.

The relevance of this discussion may not be immediately obvious. But this very simple thought experiment actually tells us something very important about the necessary conditions for consciousness to arise (mind you, not sufficient). It is a boundary condition on our theories. It also implies a counterintuitive point. The cognitive sciences tell us that while sensory stimuli originate from outside the body, they are all turned into electrical signals in the central nervous system. We don’t actually experience the outside world, what we experience is these internal signals (an oversimplification, but useful enough for this conversation). The Matrix exploited this idea brilliantly, and set up a situation where characters experienced a false world, not by presenting their senses illusory experiences, but by stimulating directly the relevant areas inside the brain, bypassing their external sensory organs completely. But if I just said that sensory experience is needed for consciousness, how are these people consciousness? The answer is tied to the internality of our conscious experience. The important point about sensory systems above can be boiled down to a very oversimplified input-computation-output-repeat system. It is not the sensory systems themselves that are integral (in theory, in practicality, they are all we have), but rather that our sensory systems facilitate interaction. Since this interaction manifests itself as internal interactions within the central nervous system, we can conceive of bypassing these external systems, as long as there was  a reliable way to stimulate the internal processes of the brain. This last point may be science fiction now, but it’s important to address the ramifications for consciousness if it was possible, since it presses our intuitions about consciousness, and thus helps us clarify some otherwise not so obvious facts.

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