Consciousness is equivalent to self awareness, coupled with the ability to act with reference to the self.
Saige is correct in pointing out that we cannot test whether or not other people or things are self aware, or are acting with reference to a self. This is because we cannot test whether or not they have a self.
This has led some to suggest that there is no self at all. Which is quite obviously rubbish, in fact, about the only thing we know for certain at all, through every waking and dreaming moment is that there is a self.
The logical positivists, amongst other spoilsports, have suggested that the perception of the self is simply a lie caused by complex things happening in the mush in our heads. This is also quite obviously rubbish, but for a different reason; if the self is a deceit, something must be being deceived, and this thing we can call the self.
Consciousness is self evidently not explicable through a mechanistic/deterministic view of the world. It is something else.
If conscious things exists, and consciousness cannot be explained by determinism, then the totality of things cannot be wholly deterministic.