Dialectic takes its general idea of reason from the higher analysis of logic, and brings the general idea to bear on concrete arguments. A dialectician makes a collection of theorems for study just as a botanist makes a collection of plants. He sorts them out into convenient classes, separates the valid or useful from the erroneous and misleading, studies the relation of language to argument and the influence for good or ill that words have upon rational thought. From the example of the vase cited above it will be seen that in every act of reason two principal things are requisite. There must be something wholly known (or comparatively well known) and something less well known, and the reasoning or argument consists in ideally completing the latter on the model of the former. If we would predict the coming of a future season of the year we must have a picture in the mind of all the seasons in the order in which they occur. If we would go straight to a place on the surface of the earth we must have a plan of the way in our imagination. If we would predict the effect of a drug on an animal body we must have previously noticed the effect it has produced--and so on. Neither the mind nor intellect supplies spontaneously any of these models; they are all formed out of actual experience remembered and recollected. When they have been refined into extremely general ideas they are apt to be taken for innate tendencies of the intellect, as Kant erroneously thought. They are not so; all we know of the intellect is consistent with the belief that it begins with pure plasm without a trace of idea, and is absolutely indifferent to the imprints it may receive. Doctrines of innate ideas--innate forms of thought or categories--innate 'principles' of various kinds--are devices of metaphysicians to cover the weakness of their theories. The two main parts of an argument divide naturally into four subdivisions. There is the thing argued about (corresponding to the broken vase); there is the ideal extension or restoration; in the model we reason from there are the parts corresponding to each of these. I propose to take terms for these four parts from one of the most important, formal and correct modes of reasoning--the application of a precedent or statute to a case in Law. XVIII--THE RATIONAL PARALLEL Every argument, whatever be the matter of it, consists in bringing a _Case_ under a _Precedent_, and applying to the case ideally the better knowledge possessed of the precedent. The _Conclusion_ (also called Inference or Deduction) is the result of this application, and is always an addition to our stock of ideas. A conclusion has never the same reality as actual experience. It is not 'true' in that sense, though it may be 'morally' true, that is, we are ready to act upon it without hesitation--to stake our life or fortune on it. As regards actual or experienced fact there can be no argument, since it is useless to 'predict' what we already know.