Definitions of truth and validity have shifted over the years nearly as much as historical interpretation. No one definition fits all. Thank goodness. Think how boring it would be if everything could be run through a formula.

Still, methods of thinking that distinguish verification from something like belief are useful. Logic and the nature of proof, the balance of reason and intuition, have been considerations since the earliest recorded utterances of humans. This text is a colloquial examination of logic; it mixes some terms and quantifies none to the satisfaction of all logicians.

The literatures of epistemology, the philosophy of history, historiography, logic, and the character of language are now almost endless. The following books are a good few with which to begin (and from which much of this section is drawn): Ayer, Language, Truth & Logic; Barzun, The Modern Researcher; Carr, What Is History?; Gottschalk, Understanding History; and Walsh, Philosophy of History. Walsh and Carr are good beginnings; Gottschalk and Barzun are practical handbooks; and Ayer gives a most incisive analysis of language, truth, and logic—exactly as his title indicates.

Epstein’s “Pre-Columbian Old World Coins” is a good example of the handling of data. For fun, see Lamb’s “Science by Litigation.” Concerning the phenomenon of “cult” science, see Cole.

The question of what evidence is admissible in scientific reasoning is quite heated in some areas, e.g., archeology, education, even history on occasion. Charles J. Cazeau and Stuart D. Scott Jr. in Exploring the Unknown examine the “pseudoscientist” and provide a good discussion of the scientific method—with examples. They include a section on “ancient mariners” (21f).

William Sims Bainbridge’s “Chariots of the Gullible” is a statistical look at von Daniken believers in extra terrestrials as well as a good comment on who is likely to believe what. For another side of things, see Fell and Totten.

Always remember that more people read the National Enquirer than the Skeptical Inquirer.