All sciences rest on a solid foundation of basic assumptions and tenets not demonstrable with the usual proof. They begin with a philosophy. Polygraphy has come a long way in its development, but its acceptance as a science by the general public will depend on common agreement as to instrumentation, physiological and psychological mechanisms, examination format, chart interpretation rules, etc. An examination of the field as a whole, however, reveals fundamental disagreements and general ambiguity regarding fundamental polygraph philosophy. There is vagueness on the basic psychology of polygraphy, difference among polygraphers in the information used to distinguish the 'guilty' from the 'innocent,' debate about how the polygraph should be used, and variation in chart interpretation rules as taught by the leading professional polygraph schools. 4 footnotes.