  The effect is far-reaching and radical. If a logical system is a concrete complex of signs, then it cannot be infinite. Also, to conform to logical practice, it has to be admitted that logical systems change over time. Ideally, they change by being added to, as new theorems are proved. In practice, they may degrade or be wholly destroyed, which was indeed the sad fate of Leśniewski’s own personally written systems in November 1944. If a logical system is published in a book or journal, and there are several copies, then there are as many such systems as there are copies. Assuming the copies are all faithful, then each copy is typographically exactly like all the others. They are, in Leśniewski’s parlance, all equiform. In practice of course, equiformity is not quite exact, even in printed works, but the minute variations are insignificant, and in any case we wish to recognize handwritten manuscripts and other variants to be equiform for logical purposes with systems which are physically somewhat different. Again the metaphysical fine detail is less important that the fact that we get by most of the time with constrainedly inexact similarity.