Any serious effort toward a consistent, coherent, and synoptic account of the place of mind in nature is fraught with embarrassing perplexities. Philosophical temperaments notoriously differ in how they react to these perplexities. Some thinkers apparently like to wallow in them and finally declare the mind-body problem unsolvable: "Ignoramus et ignorabimus." Perhaps this is an expression of intellectual masochism, or a rationalization of intellectual impotence. It may of course also be an expression of genuine humility. Others, imbued with greater confidence in the powers of philosophical insight or in the promises of scientific progress, offer dogmatic solutions of the old puzzle. And still others, recognizing the speculative and precarious character of metaphysical solutions, and deeply irritated by the many bafflements, try to undercut the whole issue and declare it an imaginary problem. But the perplexities persist and provoke further efforts — often only minor variants of older ones — toward removing this perennial bone of contention from the disputes of philosophers and scientists. Wittgenstein, who tried to "dissolve" the problem, admitted candidly [1953, Section 412]: "The feeling of an unbridgeable gulf between consciousness and brain-process…. This idea of a difference in kind is accompanied by slight giddiness," but he added quickly "which occurs when we are performing a piece of logical sleight-of-hand."