That does not follow. We can know some things indirectly without knowing everything about it. The consciousness has the property of correlation with certain functions or processes of matter. That is knowing something about it.
Like everything else, we gain more and more insight into what we are trying to understand. The consciousness is just much harder and thus progress is slower.
It most certainly does follow.
If consciousness is merely something generated by the brain then that is what it is, something generated by the brain.
Tautology is tautology. True, that.
So to claim you know what it is requires showing how it was generated not thinking it is.
A conclusion from a tautology. "So ..." {rewording what you said}->>"To claim to know what consciousness is requires showing how it was generated."
As a general pattern it is a clearly not always the case. I claim to know what an automobile is without knowing how it was generated. So what ... makes consciousness so special as to require knowledge of how it is made by the brain and neurology to know what it is.
If you can't show how it was generated claiming it was generated is an empty claim.
And the restatement of the thesis is again asserted.
There is no argument being made here. Merely assertion. One good assertion deserves another, don't you think?
It is not the case that consciousness is supernatural. Anything that occurs (for really, really reals) is the very definition of natural. Anything that affects reality is natural.
Origins are difficult. Compare gravity with consciousness:
Gravity is mysterious. Think about the state of reality with no mass so no gravity and no mass so no energy. This is "nothing." No time for anything to happen. And if that state of nothing ever were to have been the whole of reality it was, apparently, unstable. The uncertainty principle asserts itself. That is time zero. The ultimate beginning, the uncaused cause: instability.
Consciousness arises. I daresay most would agree that a fertilized ovum is unconscious. Then embryology happens and somewhere along the line a similar instability yields consciousness. One infinitesimal moment before which the answer to "is it conscious?" was "no" and in less time than it takes to say that answer it was "yes."
This is the "how" of it. The "who" of it now exists. The "what" of it is consciousness. The "where" of it is somewhere inside the human skin. The "when" is unclear. The first moment of consciousness is not remembered. The "why" is apparent evolutionary advantage for species in our size range.