It is this imaginative yet serious assertion of the vast range and possibilities of human knowledge which, as M. de Remusat remarks—­the keenest and fairest of Bacon’s judges—­gives Bacon his claim to the undefinable but very real character of greatness.  Two men stand out, “the masters of those who know,” without equals up to their time, among men—­the Greek Aristotle and the Englishman Bacon.  They agree in the universality and comprehensiveness of their conception of human knowledge; and they were absolutely alone in their serious practical ambition to work out this conception.  In the separate departments of thought, of investigation, of art, each is left far behind by numbers of men, who in these separate departments have gone far deeper than they, have soared higher, have been more successful in what they attempted.  But Aristotle first, and for his time more successfully, and Bacon after him, ventured on the daring enterprise of “taking all knowledge for their province;” and in this they stood alone.  This present scene of man’s existence, this that we call nature, the stage on which mortal life begins and goes on and ends, the faculties with which man is equipped to act, to enjoy, to create, to hold his way amid or against the circumstances and forces round him—­this is what each wants to know, as thoroughly and really as can be.  It is not to reduce things to a theory or a system that they look around them on the place where they find themselves with life and thought and power; that were easily done, and has been done over and over again, only to prove its futility.  It is to know, as to the whole and its parts, as men understand knowing in some one subject of successful handling, whether art or science or practical craft.  This idea, this effort, distinguishes these two men.  The Greeks—­predecessors, contemporaries, successors of Aristotle—­were speculators, full of clever and ingenious guesses, in which the amount of clear and certain fact was in lamentable disproportion to the schemes blown up from it; or they devoted themselves more profitably to some one or two subjects of inquiry, moral or purely intellectual, with absolute indifference to what might be asked, or what might be known, of the real conditions under which they were passing their existence.  Some of the Romans, Cicero and Pliny, had encyclopaedic minds; but the Roman mind was the slave of precedent, and was more than satisfied with partially understanding and neatly arranging what the Greeks had left.  The Arabians looked more widely about them; but the Arabians were essentially sceptics, and resigned subjects to the inevitable and the inexplicable; there was an irony, open or covert, in their philosophy, their terminology, their transcendental mysticism, which showed how little they believed that they really knew.  The vast and mighty intellects of the schoolmen never came into a real grapple with the immensity of the facts of the natural or even of the moral world; within the world of abstract thought,