If by the reasons already given, we have removed the supposition of any original bias in the mind that is inaccessible to human skill, and shown that the defects to which we are now subject are not irrevocably entailed upon us, there is another question of no less importance to be decided, before the ground can appear to be sufficiently cleared for political melioration. There is a doctrine the advocates of which have not been less numerous than those for innate principles and instincts, teaching "that the conduct of human beings in many important particulars is not determined upon any grounds of reasoning and comparison, but by immediate and irresistible impression, in defiance of the conclusions and conviction of the understanding Man is a compound being," say the favourers of this hypothesis, "made up of powers of reasoning and powers of sensation. These two principles are in perpetual hostility; and, as reason will in some cases subdue all the allurements of sense, so there are others ill which the headlong impulses of sense will for ever defeat the tardy decisions of judgement. He that should attempt to regulate man entirely by his understanding, and supersede the irregular influences of material excitement; or that should imagine it practicable by any process and in any length of time to reduce the human species under the influence of general truth; would show himself profoundly ignorant of some of the first laws of our nature."
This doctrine, which in many cases has passed so current as to be thought scarcely a topic for examination, is highly worthy of a minute analysis.
If true, it no less than the doctrine of innate principles opposes a bar to the efforts of philanthropy, and the improvement of social institutions.
Certain it is that our prospects of melioration depend upon the progress of enquiry and the general advancement of knowledge. If therefore there be points, and those important ones, in which, so to express myself, knowledge and the thinking principle in man cannot be brought into contact, if, however great be the improvement of his reason, he will not the less certainly in many cases act in a way irrational and absurd, this consideration must greatly overcloud the prospect of the moral reformer.