If true history is that of which an interior verification is possible, and is therefore history ideally contemporary and present, and if history by witnesses is lacking in truth and is not even false, but just neither false nor true (not a _hoc est_ but a _fertur_), a legitimate question arises as to the origin and function of those innumerable propositions resumed from evidence critically thrashed out and 'held to be true,' although not verified, and perhaps never to be verified, but nevertheless employed even in most serious historical treatment. When we are writing the history of the doctrine known as the _coincidentia oppositorum,_ or of the poem called _I sepolcri,_ the Latin of the Cardinal di Cusa and the verse of Foscolo obviously belong to us, both as to the thoughts and the actual words, pronounced by ourselves to ourselves, and the certainty of those historical facts is at the same time logical truth. But that the _De docta ignorantia_ was written between the end of 1439 and the early part of 1440, and Foscolo's poem on the return of the poet to Italy after his long military service in France, is evidence founded upon proofs, as to which we can only say that they are to be considered valid, because they have been to some extent _attested,_ but we cannot claim them to be true. No amount of acute mental labour upon them can prevent another document or the better reading of an old document destroying them. Nevertheless, no one will treat of the works of the Cusan or of Foscolo without availing himself of the biographical details as to their authors which have been preserved.