The brain is a biological organ, and like all other biological organs it has its limits. A human heart can only pump a certain amount of blood per minute. A human liver can only perform certain chemical reactions. The brains's limits in mental arithmetic or memorization are obvious, but is its ability to form and understand abstractions also limited?

A dog will never understand how a credit card works. Are there concepts that our human brains are biologically incapable of understanding? Maybe some of the current philosophical questions like consciousness or the illusive appearance of free will are beyond our limits.

I wish I knew more about computability, decidability, the Incompleteness Theorem etc to think further about this.