I was reading Stanford Encyclopedia's article on consciousness and the problem of "what it is like" to be a bat. I believe that there is something that it is like to be a bat, but I guess there is nothing that it is like to be a bacterium, an amoeba or even a worm or a flea. What do you think an organism has to have so that there is something that it is like to be it? Where's the divide between fleas and bats?

I think that an organism must be conscious in order for there to be something that it is like to be that organism. This may seem like an obvious truth, but some people believe that there is something it is like to be asleep even though we are not conscious when sleeping, and some people believe that there is something it is like to have unconscious desires. If you believe either of these things, then you may well believe that there is something it is like to be an animal without consciousness. But I have trouble understanding the phrase “what it is like” to be a bat without assuming (at least some sort of) consciousness on the bat’s part.

To decide whether a particular animal is conscious at a particular time, I would want to know whether it is engaged in certain sorts of information tracking. To be conscious is to be attentive in some way and being attentive, I suggest, requires one to track a given object or event across time – despite various changes in its appearance or surroundings. (A strong version of this claim would equate consciousness with information tracking. A weaker version would treat information tracking as necessary, but not sufficient, for consciousness. Either way, though, an animal’s inability to track information would indicate a lack of consciousness.) A bacterium that responds to changes in temperature without keeping track of the object that is the source of heat, or without keeping track of its own movements through space, does not pass this test.

Given the above assumptions about consciousness, and given what I know about the abilities of different animals, I would draw a dividing line between insects and fish -- concluding that there is not something that it is like to be an insect (since insects respond to stimuli without tracking objects or event) but there is something it is like to be a fish (since fish do track objects and events).

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