To the same circumstance it is owing, that improvements in moral and in political science do not strike the imagination with nearly so great force as the discoveries of the mathematician or of the chemist. When an inveterate prejudice is destroyed by extirpating the casual associations on which it was grafted, how powerful is the new impulse given to the intellectual faculties of man! Yet how slow and silent the process by which the effect is accomplished! Were it not, indeed, for a certain class of learned authors, who from time to time heave the log into the deep, we should hardly believe that the reason of the species is progressive. In this respect, the religious and academical establishments in some parts of Europe are not without their use to the historian of the human mind. Immovably moored to the same station by the strength of their cables and the weight of their anchors, they enable him to measure the rapidity of the current by which the rest of the world are borne along.
This, too, is remarkable in the history of our prejudices, that as soon as the film falls from the intellectual eye, we are apt to lose all recollection of our former blindness. Like the fantastic and giant shapes which, in a thick fog, the imagination lends to a block of stone or to the stump of a tree, they produce, while the illusion lasts, the same effect with truths and realities; but the moment the eye has caught the exact form and dimensions of its object, the spell is broken for ever, nor can any effort of thought again conjure up the spectres which have vanished.
As to the subdivisions of which the sciences of matter and of mind are susceptible, I have already said that this is not the proper place for entering into any discussion concerning them. The passages above quoted from D'Alembert, from Locke, and from Smith, are sufficient to shew how little probability there is, in the actual state of logical science, of uniting the opinions of the learned in favour of any one scheme of partition. To prefix, therefore, such a scheme to a work which is professedly to be carried on by a set of unconnected writers, would be equally presumptuous and useless; and, on the most favourable supposition, could tend only to fetter, by means of dubious
