The state of his health probably affected the nature of his philosophy, while the inner struggle between the desire for self-sufficiency and the inadequacy of his own strength must have projected itself into his understanding and evaluation of society. At once the most radical and the most conservative of men, Spencer regarded many of the so-called reform movements as signs of weakening social fibre. The only safeguard, so he thought, lay in weakening the power of the state and increasing the range of activity of private associations. Much of this later conservatism was undoubtedly temperamental and personal, as is shown in a few remarks about the stupidity of the public in so coldly receiving his books. Another result of his long invalidism was to greatly restrict his output and to force him to use second-hand material. And because of lack of material he was driven more and more into those ultimate generalizations, based largely upon reflection, which, though not standing the test of time, were extremely valuable in opening up new lines of thought and in promoting constructive and critical thinking. Free, even in youth, to develop intellectually as he wished, he was thus stimulated to unhurried, independent thinking and wholesale generalizations. The extreme activity of his mind led to the same result and also to serious errors. A bold adventure in the world of thought, Spencer's work, in spite of all these faults, was that of an intellectual pioneer and true philosopher.
This article purports to be an appreciation of Poincaré as a savant, a description of his method, and an explanation of his genius. Poincaré's reputation as a scientist is easily recognized by the fact that upon his election to the French Academy he was already a member of forty other academies. Such an achievement naturally calls for consideration and explanation. It was his ability to comprehend the ensemble of rational science, and the almost instinctive habit of searching for causes, which predestined Poincaré to become one of the most remarkable representatives of positive philosophy. His incomparable mastery of the instrument of analysis and his vast acquaintance with modern physics made of him a judge capable of appraising a theory and of pointing out its weak points and of augmenting its value. The author attributes Poincaré's genius to the functioning of the subliminal self, whose potentiality Poincare knew how to utilize. It is a well-known fact that solutions vainly sought for in the course of the day, will, after a night's rest, come to one spontaneously. Particularly is this the case with mathematics. Poincaré himself speaks of these sudden illuminations de l'esprit as "manifest signs of an anterior protracted unconscious labor."
