A foundational and highly contested question in cognitive science is whether and to what degree the brain is a modular system. This talk outlines some of the broad architectural implications of the modularity thesis, and reports on an attempt to test for them. The results indicate that the same brain regions contribute to functions across various cognitive domains, but in each domain cooperate with one another in different patterns. This does not appear to be compatible with the modularity thesis. The talk discusses the implications of the finding for the best approach to analyzing, modeling and reproducing cognitive functions in intelligent systems.