This view of the inquiry, as an analysis of the intellectual causes of doubt, will also explain one or two peculiarities in it, which, if left unnoticed, might leave an impression of its inutility. It will be seen, for example, that in the investigation of the natural history of doubt, and in the explanation of the antecedent metaphysical or critical questions which have produced it, we have indicated the schools of thought which have created it, but have abstained from insisting on the inherent necessity of the relation which subsists between the metaphysical tests of truth and the religious conclusions discussed. The reason is, that it seemed unfit to assume a side eagerly in the metaphysical controversy; and therefore, while showing that the use of certain grounds of belief and methods of inquiry has produced, both as a matter of history and logic, certain species of doubt or disbelief; we have not attempted to condemn the particular metaphysical theories on the ground of the logical consequences which are supposed to flow from them, nor to deny that they could be so amended, as either to avoid the sceptical conclusions to which our objections are taken, or be rendered innocuous by the co-existence of other causes. Science only shows the general tendency or law of logical connection between intellectual causes and effects. The production of the results in particular cases is subject to exception from the introduction of interfering causes.(1012) Another peculiarity which appertains to the analysis of the intellectual sources of doubt, besides the seeming absence of invariable necessity in their operation, might be thought to destroy the practical value of the inquiry; viz. the feeling of disappointment excited when it is perceived that they do not wholly explain the phenomenon, and are merely antecedents or elements, not causes. This arises from the very nature of mental analysis. Being in nature like chemical, it aims only at the detection of the elements that make up the compound, and furnishes the material or formal causes, not the efficient. This longing of the mind to find causes, and to discover the original motive power, is however a witness to the ineffaceable connection of the idea of power with that of will. And while it does not destroy the completeness of the analysis, as the solution of the intellectual problem proposed, it nevertheless points to the instinctive wish of the heart to resolve the causes of doubt into some ultimate source in the will; and is thus a witness to the truth of the position which we have always asserted,(1013) that the intellectual causes selected for our special study are only one branch, and must be united to the emotional in order to attain a full explanation of the phenomenon of doubt. Thus the analysis offered will have, it is hoped, a utility in the limited sphere which was claimed for it, in supplying the account of the tangled and subtle processes through which doubt has insinuated itself.