Even though no other advantage were to be obtained from our present juster views of mind, than the protection which they give, from those gross errors of inquiry to which the philosophers of so long a series of ages were exposed, this alone would surely be no slight gain. But, great as this advantage is, are we certain, that it is all which the nicest mental analysis can afford,--or rather, is it not possible at least, that we may still, in our plans of physical investigation, be suffering under the influence of errors from which we should be saved, by still juster views of the faculties employed in every physical inquiry? That we are not aware of any such influence, argues nothing; for to suppose us aware of it, would be to suppose us acquainted with the very errors which mislead us. Aquinas and Scotus, it is to be presumed, and all their contentious followers, conceived themselves as truly in the right path of physical investigation, as we do at this moment; and, though we are free from their gross mistakes, there may yet be others of which we are less likely to divest ourselves, from not having as yet the slightest suspicion of their existence. The question is not, Whether our method of inquiry be juster than theirs?--for, of our superiority in this respect, if any evidence of fact were necessary, the noble discoveries of these later years are too magnificent a proof to allow us to have any doubt,--but, Whether our plan of inquiry may not still be susceptible of improvements, of which we have now as little foresight, as the Scotists and Aquinists of the advantages which philosophy has received from the general prosecution of the inductive method? There is, indeed, no reason now to fear, that the observation of particular objects, with a view to general science, will be despised as incapable of giving any direct knowledge, and all real science be confined to universals. “Singularium _datur_ scientia.” But, though a sounder view of one intellectual process may have banished from philosophy much idle contention, and directed inquiry to fitter objects, it surely does not therefore follow, that subsequent improvements in the philosophy of mind are to be absolutely unavailing. On the contrary, the presumption unquestionably is, that if by understanding better the simple process of abstraction, we have freed ourselves from many errors in our plans of inquiry, a still clearer view of the nature and limits of all the intellectual processes concerned in the discovery of truth, may lead to still juster views of philosophizing.