David Hume would ask you, "Have you examined everywhere else, and have you examined all brains?" The point is that Hume's skepticism makes a valid point. You taking the broadest brush and declaring these abstractions are produced nowhere else but in our brains does not make it so. I will ask you to justify and warrant such a statement. I would ask you how a dead, brute nonliving universe gives rise to conciousness and sentience? How do molecules give rise to sentience? I would ask you, if materialism is true, why do you trust REASON. If mental processes are nothing but chemical reactins in the cerebral cortex, then there is no REASON to believe anything is true (including the theory of materialism and evolution). Chemicals don't evaluate whether a theory is true or not. Chemicals don't reason, they react. Thus claiming championing truth and reason, the evolutionist makes truth and reason impossible by their worldview of materialism.
Beyond that the darwinist makes, not only reason impossible in his world, but the materialists assertion that we rely on reason alone cannot be justified. This is because reason requires faith. The idea "Reason alone!" is nonsense because a defense of reason by reason is circular and therefore worthless.
Our ability to reason can come from only one of two places: either our ability arose from preexisting intelligence, or it arose from mindless matter. The materialist atheist believe, by faith, reason arose from mindless matter without intelligent intervention. We can say this because it contradicts all scientific observation, which demonstrates that an effect cannot be greater than its cause. You cannot give what you do not have to give.
Materialism cannot explain reason, logic, or truth, or any other abstract concept any more than it can explain first life. Materialism is just not reasonable.
Reason requires that this universe be a reasonable one that presupposes there is order, logic, design, and truth. Those things can only exist if there is an unchangable objectivae source and standard to judge. Science is full of presuppositions: the existence of the theory-dependent, external world, the orderly nature of the external world, the knowability of the universe, the existence of truth, the laws of logic, the reliablility of our cognitive and sensory faculties to serveas as truth gathers and as a source of justified beliefs in our intellectual environment, the adequacy of language to describe the world, the existence of 'values' used in science (i.e. test theories fairly and report test results honestly, vis-a-vis the climatologists in U.K. and Univeristy of Penn), the uniformity of nature and the efficacy of inductive reasoning, and the existence of numbers. These are just a few of the scientifically unprovable assumptions which science takes on faith in order to conduct scientific investigation.
I find it very satisfying that God constructed existence. Though I know virtually nothing of the mind of God.
Biblically, He commands that I love Him, though certain aspects of His being seem unlovable.
Thus, “If I knew God I’d be Him.”
Yet as far as I can discern, abstraction is a human construct emanating nowhere but from the human mind which, as I say, I believe God created. If you believe in any other source, by all means produce it.