Alan Turing Believed the Question "Can machines think?" to be Meaningless

Can machines (or computers) think? What did Alan Turing have to say to that question? Well, he believed that the question is too "meaningless to answer". "The original question, 'Can machines think?', I believe to be too meaningless to deserve discussion." In other words, how can we even answer that question if we don't really know what thinking actually is in the first place?