If we're to assume that consciousness only exists where it is observable, only I exist. All of you are automatons.

In fact, because of the fact that it is unobservable, you cannot even make a reasonable argument that the netbook I'm typing this on lacks consciousness.

I for example can argue that anything that is executing a series of algorithms as part of a system has consciousness, and therefore this computer is quite conscious, just as I am (even though my series of algorithms is much less well-defined and reproducible.)