The purpose of this article is to show why consciousness and thought are not manifested in digital computers. Analyzing the rationale for claiming that the formal manipulation of physical symbols in Turing machines would emulate human thought, the article attempts to show why this proved false. This is because the reinterpretation of designation and meaning to accommodate physical symbol manipulation eliminated their crucial functions in human discourse. Words have denotations and intensional meanings because the brain transforms the physical stimuli received (...) from the microworld into a qualitative, macroscopic representation for consciousness. Lacking this capacity as programmed machines, computers have no representations for their symbols to designate and mean. Unlike human beings in which consciousness and thought, with their inherent content, have emerged because of their organic natures, serial processing computers or parallel distributed processing systems, as programmed electrical machines, lack these causal capacities. (shrink)

Many philosophers, both past and present, object to materialism not from any romantic anti-scientific bent, but from sheer inability to understand the thesis. It seems utterly inconceivable to some that qualia should exist in a world which is entirely material. This paper investigates the grain objection, a much neglected argument which purports to prove that sensations could not be brain events. Three versions are examined in great detail. The plausibility of the first version is shown to depend crucially on whether (...) one holds a direct or non-direct theory of perception. Only on the latter is this version plausible. An analysis of the second "semantic" version concludes that a materialist description and explanation of the world should not be expected to transparently convey all that would be of interest or importance to human beings. The final version explicitly makes use of Grover Maxwell's non-direct perceptual theory of structural realism. Although a confusion is charged to Maxwell between phenomenal and objective properties, the critical difficulty for the grain objection is its failure to characterize "structure" from a non-percipient point of view. As the grain objection is ultimately found wanting, the real difficulty for materialism crystallizes as its irreconciliability with the mere existence of sentience, which seems to force some sort of emergence upon us. (shrink)