[34] (1) For instance, the man Peter is something real; the true idea of Peter is the reality of Peter represented subjectively, and is in itself something real, and quite distinct from the actual Peter. (2) Now, as this true idea of Peter is in itself something real, and has its own individual existence, it will also be capable of being understood--that is, of being the subject of another idea, which will contain by representation (objective) all that the idea of Peter contains actually (formaliter). (3) And, again, this idea of the idea of Peter has its own individuality, which may become the subject of yet another idea; and so on, indefinitely. (4) This everyone may make trial of for himself, by reflecting that he knows what Peter is, and also knows that he knows, and further knows that he knows that he knows, &c. (34:5) Hence it is plain that, in order to understand the actual Peter, it is not necessary first to understand the idea of Peter, and still less the idea of the idea of Peter. (6) This is the same as saying that, in order to know, there is no need to know that we know, much less to know that we know that we know. (7) This is no more necessary than to know the nature of a circle before knowing the nature of a triangle. [n]. (8) But, with these ideas, the contrary is the case: for, in order to know that I know, I must first know. [35] (1) Hence it is clear that certainty is nothing else than the subjective essence of a thing: in other words, the mode in which we perceive an actual reality is certainty. (2) Further, it is also evident that, for the certitude of truth, no further sign is necessary beyond the possession of a true idea: for, as I have shown, it is not necessary to know that we know that we know. (3) Hence, again, it is clear that no one can know the nature of the highest certainty, unless he possesses an adequate idea, or the subjective essence of a thing: certainty is identical with such subjective essence. [36] (1) Thus, as the truth needs no sign--it being to possess the subjective essence of things, or, in other words, the ideas of them, in order that all doubts may be removed--it follows that the true method does not consist in seeking for the signs of truth after the acquisition of the idea, but that the true method teaches us the order in which we should seek for truth itself, [o] or the subjective essences of things, or ideas, for all these expressions are synonymous. [37] (1) Again, method must necessarily be concerned with reasoning or understanding--I mean, method is not identical with reasoning in the search for causes, still less is it the comprehension of the causes of things: it is the discernment of a true idea, by distinguishing it from other perceptions, and by investigating its nature, in order that we may so train our mind that it may, by a given standard, comprehend whatsoever is intelligible, by laying down certain rules as aids, and by avoiding useless mental exertion.