Now, in the development of instruments generally, we may distinguish a rule-of-thumb or more or less unreflective stage of construction, and one entirely reflective. As to use there is the distinction of inexpert and expert control. This leads us to expect that in the thought-function also certain typical stages of construction and of control may be found. To the investigation of this point we shall next direct attention. II In its development from crude to expert forms judgment exhibits three typical stages--_the impersonal_, _the reflective_, and _the intuitive_. These we shall consider in order of development. But first it is to be noticed that these stages of judgment are not to be regarded as hard and fast distinctions of the kind that no indications of the higher are to be found in the lower types, but rather as working distinctions within a process of continuous development. 1. _The impersonal judgment._--Ever since the days of the Greek grammarians the impersonal judgment has been considered an anomaly in logic. And the reason is not far to seek. From the time of Aristotle it has been customary to maintain that judgments, when analyzed, disclose a subject and a predicate. Logically considered, these appear to be entirely correlative, for, as Erdmann puts it,[55] "an event without a substrate, a quality without a subject, is altogether unpresentable." But there is in all languages a class of judgments, such as, "It rains," "It snows," "Fire!" in which no directly asserted subject is discoverable. To these the name impersonal and subjectless has been given. Here then is the difficulty. If we admit that the impersonal expression involves predication, we must, in all consistency, search for a subject, while at the same time the subject refuses to disclose itself. In ancient days the orthodox logician confined his search to language and to the spoken or written proposition. The unorthodox critic maintained, in opposition to this, that a subject was provided only by warping and twisting the natural sense of the impersonal expression. And thus the matter stood until the development of modern comparative philology. It was then demonstrated beyond the possibility of doubt that the "it" (or its equivalent) of the impersonal is a purely contentless form word. Language provides no subject whatsoever. So strong, however, is the hold of tradition that the search has been renewed. Attention has been turned upon the mental processes involved, and this time with more apparent result. Although there has been no general agreement with reference to the subject, a classification of the different views may still be made. (_a_) The subject is universal and undetermined; (_b_) it is individual and more or less determined; (_c_) between these extremes lies almost every intermediate degree conceivable.