Does consciousness produce any measurable effect? For a time I thought consciousness is some kind of by-product of some kinds of computation which doesn't influence the computation itself. But how can I then know that I am conscious? And if I know that I am conscious, then consciousness must have a measurable effect, right? Because the knowledge that you are conscious should be reflected somewhere in your brain.

However, whenever I think about consciousness, I have the feeling that I am missing something obvious but important. It's just so confusing.