1.  The man of common sense, (so called,) who aspires to be somewhat of a philosopher, will face the question boldly, and will say, “I feel that colour and hardness, for instance, lie entirely within the sphere of sense, and are mere modifications of my subjective nature.  At the same time, feel that colour and hardness constitute a real object, which exists out of the sphere of sense, independently of me and all my modifications. How this should be, I know not; I merely state the fact as I imagine myself to find it.  The modus is beyond my comprehension.”  This man belongs to the school of Natural Realists.  If he merely affirmed or postulated a miracle in what he uttered, we should have little to say against him, (for the whole process of sensation is indeed miraculous.) But he postulates more than a miracle; he postulates a contradiction, in the very contemplation of which our reason is unhinged.

2.  Another man will deny that our sensations ever transcend the sphere of sense, or attain a real objective existence.  “Colour, hardness, figure, and so forth,” he will say, “are generated within the sphere of sense, in obedience to its own original laws.  They form integral parts of the sphere; and he who endeavours to construe them to his own mind as embodied in extrinsic independent existences, must for ever be foiled in the attempt.”  This man declines giving any answer to the problem.  We ask, how can our sensations be embodied in distinct permanent realities?  And he replies, that they never are and never can be so embodied.  This man is an Idealist—­or as we would term him, (to distinguish him from another species about to be mentioned, of the same genus,) an Acosmical idealist; that is, an Idealist who absolutely denies the existence of an independent material world.

3.  A third man will postulate as the cause of our sensations of hardness, colour, &c., a transcendent something, of which he knows nothing, except that he feigns and fables it as lying external to the sphere of sense:  and then, by referring our sensations to this unknown cause, he will obtain for them, not certainly the externality desiderated, but a quasi-externality, which he palms off upon himself and us as the best that can be supplied.  This man is Cosmothetical Idealist:  that is, an Idealist who postulates an external universe as the unknown cause of certain modifications we are conscious of within ourselves, and which, according to his view, we never really get beyond.  This species of speculator is the commonest, but he is the least trustworthy of any; and his fallacies are all the more dangerous by reason of the air of plausibility with which they are invested.  From first to last, he represents us as the dupes of our own perfidious nature.  By some inexplicable process of association, he refers certain known effects to certain unknown causes; and would thus explain to us how these effects (our sensations) come to assume,