o be "thick as a brick" isn't about being dense, or being stupid...its a statement on humanity. Think about what a brick is made of....clay, hardened and used to build. Man is clay, hardened. Wise men have ideologies, but they aren't real....men are real creatures forged of ideas, knowledge and experience, and hardened by loss, sadness and pain.
I know, sounds like bull....but the metaphors in the album are so vast, and for the most part so confusing, that you have to take your clues form the little lines that most don't remember....

"Let me tell you the tales of your life of
your love and the cut of the knife
the tireless oppression
the wisdom instilled
the desire to kill or be killed.
Let me sing of the losers who lie in the street as the last bus goes by.
The pavements are empty: the gutters run red -- while the fool
toasts his god in the sky."