All knowledge is limited to the relative, and consists in increasing generalization:  the apex of this pyramid is formed by philosophy.  Common knowledge is un-unified knowledge; science is partially unified knowledge; philosophy, which combines the highest generalizations of the sciences into a supreme one, is completely unified knowledge.  The data of philosophy are—­besides an Unknowable Power—­the existence of knowable likenesses and differences among its manifestations, and a resulting segregation of the manifestations into those of subject and object.  Further, derivative data are space (relations of coexistence), time (relations of irreversible sequence), matter (coexistent positions that offer resistance), motion (which involves space, time, and matter), and force, the ultimate of ultimates, on which all others depend, and from our primordial experiences of which all the other modes of consciousness are derivable.  Similarly the ultimate primary truth is the persistence of force, from which, besides the indestructibility of matter and the continuity of (actual or potential) motion, still further truths may be deduced:  the persistence of relations among forces or the uniformity of law, the transformation and equivalence of (mental and social as well as of physical) forces, the law of the direction of motion (along the line of least resistance, or the line of greatest traction, or their resultant), and the unceasing rhythm of motion.  Beyond these analytic truths, however, philosophy demands a law of universal synthesis.  This must be the law of the continuous redistribution of matter and motion, for each single thing, and the whole universe as well, is involved in a (continuously repeated) double process of evolution and dissolution, the former consisting in the integration of matter[1] and the dissipation of motion, the latter in the absorption of motion and the disintegration of matter.  The law of evolution, in its complete development, then runs:  “Evolution is an integration of matter and concomitant dissipation of motion; during which the matter passes from an indefinite, incoherent homogeneity to a definite, coherent heterogeneity; and during which the retained motion undergoes a parallel transformation.”  This is inductively supported by illustrations from every region of nature and all departments of mental and social life; and, further, shown deducible from the ultimate principle of the persistence of force, through the mediation of several corollaries to it, viz., the instability of the homogeneous under the varied incidence of surrounding forces, the multiplication of effects by action and reaction, and segregation.  Finally the principle of equilibration indicates the impassable limit at which evolution passes over into dissolution, until the eternal round is again begun.  If it may be said of Hegel himself, that he vainly endeavored to master the concrete fullness of reality with formal concepts, the criticism is applicable to Spencer in still greater measure.  The barren schemata of concentration, passage into heterogeneity, adaptation, etc., which are taken from natural science, and which are insufficient even in their own field, prove entirely impotent for the mastery of the complex and peculiar phenomena of spiritual life.