Does Consciousness Come in Degrees?

William Lycan at the Institute of Art and Ideas:

A creature that does perceive the external world to any significant degree can be called a conscious being.  Could there be conscious beings other than those of earth’s animal kingdom?  Perhaps there are some outside our solar system. Could a robot be a conscious being, just in this modest sense of perceiving its environment?  I don’t see why not.  Despite appearances, a robot can amass information through its sensors and build a representation of the external world.  Granted, there are plenty of arguments purporting to show that no mere robot could be conscious in any much stronger sense.

Of course we can also ask whether a conscious creature in that sense is ‘conscious’ at a particular time, say at this moment, meaning roughly, is it awake, actually doing some perceiving, and in control of its actions?  Even that ‘normal waking state’ admits some degrees, since we speak of accident victims and seriously ill patients as ‘semi-conscious.’

A much rarer form of consciousness is what we refer to when we speak of a ‘conscious memory’ or a ‘conscious decision’—we mean not only being in a mental state but being aware of that very mental state from the inside. A conscious memory is a memory we are directly aware of.  The same goes for a conscious emotion, desire, intention, or bodily sensation such as pain.  It’s assumed that there are memories, emotions, desires, intentions, perceptions, and even pains that we are unaware of, at least at times.

More here.