Question: In class we are discussing skepticism, and we are trying to make the distinction between the dream state and awake.
I have made the case in class as follows: first "I think therefore I am": the mere fact that we are thinking of these issues implies that we have consciousness. If we have consciousness, then there must be existence in which our consciousness presides. Ergo, existence precedes consciousness.
Working from that conclusion, we can simply test this out by the fact that in dreams our will can affect 'reality' and hence violate the law of existence before consciousness. Now the point that is missing is how do we determine reality from dream in all cases? Given the above conclusion, we would only be able to determine times in which our dreams are those that we are able to control, but does that mean that all dreams are able to be controlled? Seemingly, the answer is no, one cannot tell for certain the difference between dreams and awakeness in ALL cases. However, this is terribly difficult for me to accept without further investigation. Is there any guidance that you may be able to offer?
Answer: How do you know what a dream is in the first place? You know it by contrasting it with being awake (i.e., being conscious and aware of the world).
A dream is state in which you seem to experience some of the aspects of being conscious. Actually, dreams do not provide the detailed direct external awareness we have in perception, but we often feel as if they are real because when we are dreaming emotional and intuitive reasoning aspects of our minds are stimulated. Perhaps you've had this experience: a dream that seemed extremely vivid and moving, but about which the details are not clear, or in which the details are actually a silly jumble once you reflect on them.
The basic point is that the fact that we are conscious is self-evident. It is a fundamental, axiomatic fact underlying all philosophical reasoning. It is against the undeniable background of full conscious awareness that we contrast the state of dreaming, and know the difference between being asleep and awake.