Scepcop,
I think the term "Palmistry" is an umbrella covering a vast number of disciplines and collections of lore encompassing fact, science, superstition, folklore, psychology, genetic research, interpretive skill and medical diagnosis. I've studied and continue to study all of these aspects of this misunderstood field, which is as noted, actually many fields.
In its classical form, it's a philosophical system based on Greco-Roman archetypes used by reader/participant to explore inquiries of a spiritual or psychological nature.
This is why the strictly rational, materialist analysis of Palmistry fails to grasp the essence of the craft and it's often dismissed as fortune telling or cold reading. Scientific methods simply cannot be applied to a philosophical system. You can't "prove" theism, Buddhism, ontology, existentialism, Palmistry, Astrology etc because these are philosophical systems designed for making inquiries of a spiritual nature, not for forming, testing, and falsifying hypotheses about the physical universe.
This misunderstanding, more than anything else--attempting to apply the scientific method to what are in essence philosophical systems--is the source of so much confusion (and often bitter debate) between the practitioners of these systems and the skeptics.
JSG