[210] The idea that our “demonstrable knowledge is very short, if indeed we have any at all, although our certainty is as great as our happiness, beyond which we have no concernment to know or to be” (Essay, iv. 2–14); or Locke’s words: “I have always thought the actions of men the best interpreters of their thoughts.”
[211] Schopenhauer, for example, used to be fond of repeating that his own philosophy (which took will to be the fundamental reality) was on its very face necessarily more of an ethic than a system like that of Spinoza, for example, which could only be called an ethic by a sort of lucus a non lucendo.
[212] The Practical Reason to Aristotle is the reason that has to do with the pursuit of aims and ends, in distinction from the reason that has to do with knowledge, and the “universal” and science. This twofold distinction has given many problems to his students and to his commentators, and to succeeding generations. It is responsible for the entire mediæval and Renaissance separation of the intellectual life and the intellectual virtues from the practical life and the practical virtues.
[213] It might be added here that Logic has always recognized the validity, to some extent, of the argument “from consequences” of which Pragmatism makes so much. The form of argumentation that it calls the Dilemma is a proof of this statement. A chain of reasoning that leads to impossible consequences, or that leads to consequences inconsistent with previously admitted truths, is necessarily unsound. That this test of tenable or untenable consequences has often been used in philosophy in the large sense of the term must be known only too well to the well-informed reader. As Sidgwick says in his Method of Ethics: “The truth of a philosopher’s premises will always be tested by the acceptability of his conclusions; if in any important point he is found in flagrant conflict with common opinion, his method will be declared invalid.” Reid used the argument from consequences in his examination of the sceptical philosophy of Hume. It is used with effect in Mr. Arthur Balfour’s Foundations of Belief in regard to the supposed naturalism of physical science. Edmund Burke applied it to some extent to political theories, or to the abstract philosophical theories upon which some of them were supposedly based.
[214] Pragmatism has been called by some critics a “new-Humism” on the ground of its tendency to do this very thing that is mentioned here in respect of Hume. But the justice or the injustice of this appellation is a very large question, into which it is needless for us to enter here.
[215] Cf. “Intelligence is the aptitude to modify conduct in conformity to the circumstances of each case” (The Positive Philosophy, Martineau, i. 465).
[216] Principles of Philosophy, Part II. iii. It is also an eminently pragmatist idea on the part of Descartes to hold that “I should find much more truth in the reasoning of each individual with reference to the affairs in which he is personally interested, and the issue of which must presently punish him if he has judged amiss, than in those conducted by a man of letters in his study, regarding speculative matters that are of no practical moment” (Method, Veitch’s edition, p. 10).
[217] Principles of Philosophy, Part II. iii. p. 233.
[218] See Principles of Psychology, ch. ii., “Assumption of Metaphysicians,” and also elsewhere in his Essays.
[219] “Any power of doing or suffering in a degree however slight was held by us to be the definition of existence” (Sophist, Jowett’s Plato, iv. p. 465).