Everything in the universe is supposed to be made of entities called "atoms?

Everything in the universe is supposed to be made of entities called "atoms". Therefore, the brain is made of atoms. The brain is presumably the mechanism through which we perceive (and attain our understanding of) the universe. But, how can we gain any real understanding of the universe (which, since the universe is made of atoms, is equivalent to gaining an understanding of atoms) by using the very entities (atoms, which make up the brain) that we're trying to understand? Isn't there something circular going on here? Comment