impossibility or necessity; if I truly understood either one or the
other I should not be able to feign, and I should be reduced to saying
that I had made the attempt.

[57] (1) It remains for us to consider hypotheses made in problems,
which sometimes involve impossibilities. (2) For instance, when we
say - let us assume that this burning candle is not burning, or,
let us assume that it burns in some imaginary space, or where there
are no physical objects. (3) Such assumptions are freely made,
though the last is clearly seen to be impossible. (4) But, though
this be so, there is no fiction in the case. (57:5) For, in the first
case, I have merely recalled to memory, [x] another candle not
burning, or conceived the candle before me as without a flame, and
then I understand as applying to the latter, leaving its flame out
of the question, all that I think of the former. (6) In the second
case, I have merely to abstract my thoughts from the objects
surrounding the candle, for the mind to devote itself to the
contemplation of the candle singly looked at in itself only; I can
then draw the conclusion that the candle contains in itself no
causes for its own destruction, so that if there were no physical
objects the candle, and even the flame, would remain unchangeable,
and so on. (7) Thus there is here no fiction, but, [y] true and
bare assertions.

[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