Limits of (human) thought?

In his paper "The Problem of Philosophy" and his book "Problems in Philosophy", Wiley, 1993 Colin McGinn argues that "The human mind conforms to certain principles in forming concepts and beliefs and theories...and these constrain the range of knowledge to which we have access." In some areas of inquiry "the correct theory is inaccessible to the human intellect."
But the whole idea of "learning" is to have access to patterns you have never seen before.  The mind is an open system. Things get added to it from without.  It can also employ external memory storage (notes, books, libraries, etc.) to augment its capability.