It remains to glance at another aspect of the dialectic method first developed on a great scale by Plato, and first fully defined by Aristotle, but already playing a certain part in the Socratic teaching. This is the testing of common assumptions by pushing them to their logical conclusion, and rejecting those which lead to consequences inconsistent with themselves. So understood, dialectic means the complete elimination of inconsistency, and has ever since remained the most powerful weapon of philosophical criticism. To take an instance near at hand, it is constantly employed by thinkers so radically different as Mr. Herbert Spencer and Professor T. H. Green; while it has been generalised into an objective law of Nature and history, with dazzling though only momentary success, by Hegel and his school. VI. Consistency is, indeed, the one word which, better than any other, expresses the whole character of Socrates, and the whole of philosophy as well. Here the supreme conception of mind reappears under its most rigorous, but, at the same time, its most beneficent aspect. It is the temperance which no allurement can surprise; the fortitude which no terror can break through; the justice which eliminates all personal considerations, egoistic and altruistic alike; the truthfulness which, with exactest harmony, fits words to meanings, meanings to thoughts, and thoughts to things; the logic which will tolerate no self-contradiction; the conviction which seeks for no acceptance unwon by reason; the liberalism which works through free agencies for freedom; the love which wills another’s good for that other’s sake alone.[98] It was the intellectual passion for consistency which made Socrates so great and which fused his life into a flawless whole; but it was an unconscious motive power, and therefore he attributed to mere knowledge what knowledge alone could not supply. A clear perception of right cannot by itself secure the obedience of our will. High principles are not of any value, except to those in whom a discrepancy between practice and profession produces the sharpest anguish of which their nature is capable; a feeling like, though immeasurably stronger than, that which women of exquisite sensibility experience when they see a candle set crooked or a table-cover awry. How moral laws have come to be established, and why they prescribe or prohibit certain classes of actions, are questions which still divide the schools, though with an increasing consensus of authority on the utilitarian side: their ultimate sanction—that which, whatever they are, makes obedience to them truly moral—can hardly be sought elsewhere than in the same consciousness of logical stringency that determines, or should determine, our abstract beliefs.