The technical formulation of this view is contained in his _Logic_. This book may indeed be said to be Hegel's master-stroke. Nothing less is attempted in it than the proof that the very process of reasoning manifests the same principle of evolution through a union of opposites. Hegel was well aware, as much as recent exponents of anti-intellectualism, that through "static" concepts we transmute and falsify the "fluent" reality. As Professor James says "The essence of life is its continuously changing character; but our concepts are all discontinuous and fixed ... When we conceptualize we cut out and fix, and exclude everything but what we have fixed. A concept means a _that-and-no-other_." But are our concepts static, fixed, and discontinuous? What if the very concepts we employ in reasoning should exemplify the universal flow of life? Hegel finds that indeed to be the case. Concepts we daily use, such as quality and quantity, essence and phenomenon, appearance and reality, matter and force, cause and effect, are not fixed and isolated entities, but form a continuous system of interdependent elements. Stated dogmatically the meaning is this: As concavity and convexity are inseparably connected, though one is the very opposite of the other--as one cannot, so to speak, live without the other, both being always found in union--so can no concept be discovered that is not thus wedded to its contradiction. Every concept develops, upon analysis, a stubbornly negative mate. No concept is statable or definable without its opposite; one involves the other. One cannot speak of motion without implying rest; one cannot mention the finite without at the same time referring to the infinite; one cannot define cause without explicitly defining effect. Not only is this true, but concepts, when applied, reveal perpetual oscillation. Take the terms "north" and "south." The mention of the north pole, for example, implies at once the south pole also; it can be distinguished only by contrast with the other, which it thus _includes_. But it is a north pole only by _excluding_ the south pole from itself--by being itself and not merely what the other is not. The situation is paradoxical enough: Each aspect--the negative or the positive--of anything appears to exclude the other, while each requires its own other for its very definition and expression. It needs the other, and yet is independent of it. How Hegel proves this of all concepts, cannot here be shown. The result is that no concept can be taken by itself as a "that-and-no-other." It is perpetually accompanied by its "other" as man is by his shadow. The attempt to isolate any logical category and regard it as fixed and stable thus proves futile. Each category--to show this is the task of Hegel's _Logic_--is itself an organism, the result of a process which takes place within its inner constitution. And all logical categories, inevitably used in describing and