Now it so happens that when the facts of error were consciously generalized and formulated, namely in Greek thought, such a technique of specific inquiry and rectification did not exist--in fact, it hardly could come into existence until _after_ error had been seized upon as constituting a fundamental anomaly. Hence the method just outlined of dealing with the situation was impossible. We can imagine disconsolate ghosts willing to postpone any professed solution of the difficulty till subsequent generations have thrown more light on the question itself; we can hardly imagine passionate human beings exercising such reserve. At all events, Greek thought provided what seemed a satisfactory way out: there are two orders of existence, one permanent and complete, the noumenal region, to which alone the characteristic of Being is properly applicable, the other transitory, phenomenal, sensible, a region of non-Being, or at least of mere Coming-to-be, a region in which Being is hopelessly mixed with non-Being, with the unreal. The former alone is the domain of knowledge, of truth; the latter is the territory of opinion, confusion, and error. In short, the contrast _within_ experience of the cases in which things successfully and unsuccessfully maintained and executed the meanings of other things was erected into a wholesale difference of status in the intrinsic characters of the things involved in the two types of cases. With the beginnings of modern thought, the region of the “unreal,” the source of opinion and error, was located exclusively in the individual. The object was _all_ real and _all_ satisfactory, but the “subject” could approach the object only through his own subjective states, his “sensations” and “ideas.” The Greek conception of two orders of existence was retained, but instead of the two orders characterizing the “universe” itself, one _was_ the universe, the other was the individual mind trying to know that universe. This scheme would obviously easily account for error and hallucination; but how could _knowledge_, truth, ever come about such a basis? The Greek problem of the possibility of error became the modern problem of the possibility of knowledge.