When Wittgenstein climbed the stairs muttering "I get stuipider and stupider every day."

Freeman Dyson writes:

 "When I arrived at Cambridge University in 1946, Wittgenstein had just returned from his six years of duty at the hospital. I held him in the highest respect and was delighted to find him living in a room above mine on the same staircase. I frequently met him walking up or down the stairs, but I was too shy to start a conversation. Several times I heard him muttering to himself                                             

 “I get stupider and stupider every day.”