Self-evident truths are axiomatic, necessary, and universal, such as "All the radii of a given circle are equal", or "The whole is greater than its part". Truths that are not self-evident may change, if the facts change, as, for instance, "The pen I hold in my hand is six inches long". There are necessary truths, which are a legitimate standard by which to test new truths; and there are truths of fact, which, as long as they remain true, are also legitimate tests of new truth. Thus, systems of truth are built up, and part of the system may be axiomatic truths, which need not be re-made or made over when a new truth is acquired.
All this is swept aside by the Pragmatist with the same contempt as the naive realism which holds that concepts represent reality. There are no necessary truths, there are no axioms, says Pragmatism, but only postulates. A judgment is true if it functions in such a way as to explain our experiences, and it continues to be true only so long as it does explain our experiences. The apparent self-evidence of axioms, says the Pragmatist, is due, not to the clearness and cogency of the evidence arising from an analysis of concepts, much less is it due to the cogency of reality; it is due to a long-established habit of the race. The reason why I cannot help thinking that two and two are four is the habit of so thinking, a habit begun by our ancestors before they were human and indulged in by all their descendants ever since. All truths are, therefore, empirical: they are all "man-made"; hence Humanism is only another name for Pragmatism. Our judgments being all personal, in this sense, and based on our own experience, subject to the limitations imposed by the habits of the race, it follows that the conclusions which we draw from them when we reason are only hypothetical. They are valid only within our experience, and should not be carried beyond the region of verifiable experience. Pragmatism, as James pointed out, does not look backward to axioms, premises, systems, but forward to consequences, results, fruits. In point of fact, then, we are, if we believe the Pragmatist, obliged to subscribe to the doctrine of John Stuart Mill that all truth is hypothetical, that "can be" and "cannot be" have reference only to our experience, and that, for all we know, there may be in some remote region of space a country where two and two are five, and a thing can be and not be at the same time.
