ABSTRACT
Like most words, consciousness does not admit of a definition in terms of genus and differentia or necessary and sufficient conditions. Nonetheless, it is important to say exactly what we are talking about because the phenomenon of consciousness that we are interested in needs to be distinguished from certain other phenomena such as attention, knowledge, and self-consciousness. By consciousness, I simply mean those subjective states of sentience or awareness that begin when one
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Above all, consciousness is a biological phenomenon. We should think of consciousness as part of our ordinary biological history, along with digestion, growth, mitosis, and meiosis. However, though consciousness is a biological phenomenon, it has some important features that other biological phenomena do not have. The most important of these is what I have called its subjectivity. There is a sense in which each person's consciousness is private to that person, a sense in which he is related to his pains, tickles, itches, thoughts, and feelings in a way that is quite unlike the way that others are related to those pains, tickles, itches, thoughts, and feelings. This phenomenon can be described in various ways. It is sometimes described as that feature of consciousness by way of which there is something that it is like or something that it feels like to be in a certain conscious state. If somebody asks me what it feels like to give a lecture in front of a large audience, I can answer that question. But if somebody asks what it feels like to be a shingle or a stone, there is no answer to that question because shingles and stones are not conscious. The point is also put by saying that conscious states have a certain qualitative character; the states in question are sometimes described as qualia. In spite of its etymology, consciousness should not be confused with knowledge, it should not be confused with attention, and it should not be confused with self-consciousness. I consider each of these confusions in turn.
