[58] (1) Let us now pass on to the fictions concerned with essences only, or with some reality or existence simultaneously. (2) Of these we must specially observe that in proportion as the mind's understanding is smaller, and its experience multiplex, so will its power of coining fictions be larger, whereas as its understanding increases, its capacity for entertaining fictitious ideas becomes less. (58:3) For instance, in the same way as we are unable, while we are thinking, to feign that we are thinking or not thinking, so, also, when we know the nature of body we cannot imagine an infinite fly; or, when we know the nature of the soul, [z] we cannot imagine it as square, though anything may be expressed verbally. (4) But, as we said above, the less men know of nature the more easily can they coin fictitious ideas, such as trees speaking, men instantly changed into stones, or into fountains, ghosts appearing in mirrors, something issuing from nothing, even gods changed into beasts and men and infinite other absurdities of the same kind. [59] (1) Some persons think, perhaps, that fiction is limited by fiction, and not by understanding; in other words, after I have formed some fictitious idea, and have affirmed of my own free will that it exists under a certain form in nature, I am thereby precluded from thinking of it under any other form. (2) For instance, when I have feigned (to repeat their argument) that the nature of body is of a certain kind, and have of my own free will desired to convince myself that it actually exists under this form, I am no longer able to hypothesize that a fly, for example, is infinite; so, when I have hypothesized the essence of the soul, I am not able to think of it as square, &c. [60] (1) But these arguments demand further inquiry. (2) First, their upholders must either grant or deny that we can understand anything. If they grant it, then necessarily the same must be said of understanding, as is said of fiction. (3) If they deny it, let us, who know that we do know something, see what they mean. (4) They assert that the soul can be conscious of, and perceive in a variety of ways, not itself nor things which exist, but only things which are neither in itself nor anywhere else, in other words, that the soul can, by its unaided power, create sensations or ideas unconnected with things. (5) In fact, they regard the soul as a sort of god. (60:6) Further, they assert that we or our soul have such freedom that we can constrain ourselves, or our soul, or even our soul's freedom. (7) For, after it has formed a fictitious idea, and has given its assent thereto, it cannot think or feign it in any other manner, but is constrained by the first fictitious idea to keep all its other thoughts in harmony therewith. (8) Our opponents are thus driven to admit, in support of their fiction, the absurdities which I have just enumerated; and which are not worthy of rational refutation.