Error may arise in two ways, either in the matter, or in the form of an argument; either, that is, by assuming to be true what is false, or by transgressing the laws of the syllogism. The Philosopher raised objections to the arguments of Parmenides and Melissus on both of these grounds, saying that they accepted what was false, and that they did not argue correctly.[286] I use "false" in a large sense, as including the inconceivable,[287] that which in matters admitting only of probability has the nature of falseness. If the error is in the form of an argument, he who wishes to destroy the error must do so by showing that the laws of the syllogism have been transgressed. If the error is in the matter, it is because something has been assumed which is either false in itself, or false in relation to that particular instance. If the assumption is false in itself, the argument must be destroyed by destroying the assumption; if it is false only in that particular instance, we must draw a distinction between the falseness in that particular instance and its general truth. [Footnote 286: Aristotle, _Phys._ i. 2.--(W.)] [Footnote 287: "_Inopinabili._"] Having noted these things, to make it more clear how we destroy this and the further fallacies of our adversaries, we must remark that there are two ways in which error may arise concerning the mystical sense, either by seeking it where it is not, or by accepting it in a sense other than its real sense. On account of the first of these ways, Augustine says, in his work _Of the City of God_,[288] that we must not think that all things, of which we are told, have a special meaning; for it is on account of that which means something, that that also which means nothing is woven into a story. It is only with the ploughshare that we turn up the earth; but the other parts of the plough are also necessary. [Footnote 288: Dante does not quote St. Augustine's words, but gives his meaning, xvii. 2.--(W.)]