Unless it can be asserted that mankind did not know anything until logicians taught it to them that until the last hand has been put to a moral truth by giving it a metaphysically precise expression, all the previous rough-hewing which it has undergone by the common intellect at the suggestion of common wants and common experience is to go for nothing; it must be allowed, that even the originality which can, and the courage which dares, think for itself, is not a more necessary part of the philosophical character than a thoughtful regard for previous thinkers, and for the collective mind of the human race. What has been the opinion of mankind, has been the opinion of persons of all tempers and dispositions, of all partialities and prepossessions, of all varieties in position, in education, in opportunities of observation and inquiry. No one inquirer is all this; every inquirer is either young or old, rich or poor, sickly or healthy, married or unmarried, meditative or active, a poet or a logician, an ancient or a modern, a man or a woman; and if a thinking person, has, in addition, the accidental peculiarities of his individual modes of thought. Every circumstance which gives a character to the life of a human being, carries with it its peculiar biases; its peculiar facilities for perceiving some things, and for missing or forgetting others. But, from points of view different from his, different things are perceptible; and none are more likely to have seen what he does not see, than those who do not see what he sees. The general opinion of mankind is the average of the conclusions of all minds, stripped indeed of their choicest and most recondite thoughts, but freed from their twists and partialities: a net result, in which everybody's point of view is represented, nobody's predominant. The collective mind does not penetrate below the surface, but it sees all the surface; which profound thinkers, even by reason of their profundity, often fail to do: their intenser view of a thing in some of its aspects diverting their attention from others.
The hardiest assertor, therefore, of the freedom of private judgment the keenest detector of the errors of his predecessors, and of the inaccuracies of current modes of thought -- is the very person who most needs to fortify the weak side of his own intellect, by study of the opinions of mankind in all ages and nations, and of the speculations of philosophers of the modes of thought most opposite to his own. It is there that he will find the experiences denied to himself -- the remainder of the truth of which he sees but half -- the truths, of which the errors he detects are commonly but the exaggerations. If, like Bentham, he brings with him an improved instrument of investigation, the greater is the probability that he will find ready prepared a rich abundance of rough ore, which was merely waiting for that instrument. A man of clear ideas errs grievously if he imagines that whatever is seen confusedly does not exist: it belongs to him, when he meets with such a thing, to dispel the mist, and fix the outlines of the vague form which is looming through it.
Bentham's contempt, then, of all other schools of thinkers;his determination to create a philosophy wholly out of the materials furnished by his own mind, and by minds like his own;was his first disqualification as a philosopher. His second, was the incompleteness of his own mind as a representative of universal human nature. In many of the most natural and strongest feelings of human nature he had no sympathy; from many of its graver experiences he was altogether cut off; and the faculty by which one mind understands a mind different from itself, and throws itself into the feelings of that other mind, was denied him by his deficiency of Imagination.
With Imagination in the popular sense, command of imagery and metaphorical expression, Bentham was, to a certain degree, endowed. For want, indeed, of poetical culture, the images with which his fancy supplied him were seldom beautiful, but they were quaint and humorous, or bold, forcible, and intense: passages might be quoted from him both of playful irony, and of declamatory eloquence, seldom surpassed in the writings of philosophers. The Imagination which he had not, was that to which the name is generally appropriated by the best writers of the present day; that which enables us, by a voluntary effort, to conceive the absent as if it were present, the imaginary as if it were real, and to cloth it in the feelings which, if it were indeed real, it would bring along with it. This is the power by which one human being enters into the mind and circumstances of another. This power constitutes the poet, in so far as he does anything but melodiously utter his own actual feelings. It constitutes the dramatist entirely. It is one of the constituents of the historian; by it we understand other times; by it Guizot interprets to us the middle ages; Nisard, in his beautiful Studies on the later Latin poets, places us in the Rome of the Caesars; Michelet disengages the distinctive characters of the different races and generations of mankind from the facts of their history. Without it nobody knows even his own nature, further than circumstances have actually tried it and called it out; nor the nature of his fellow-creatures, beyond such generalizations as he may have been enabled to make from his observation of their outward conduct.
