false or, while it may admit of being false, is prevented from being false by circumstances external to itself, as " Virtue is beneficial." Not necessary is that which, while true, yet is capable of being false if there are no external conditions to prevent, e.g. Dion is walking." A reasonable proposition is one which has to start with more chances of being true than not, e.g. " I shall be alive to-morrow." And there are other shades of difference in propositions and grades of transition from true to false and conversions of their terms — which we now go on to describe broadly. An argument, according to the followers of Crinis, consists of a major premiss, a minor premiss, and a conclusion, such as for example this : " If it is day, it is light ; but it is day, therefore it is light." Here the sentence " If it is day, it is light " is the major premiss, the clause "it is day " is the minor premiss, and " therefore it is light " is the conclusion. A mood is a sort of outline of an argument, like the following : "If the first, then the second ; but the first is, therefore the second is." Symbolical argument is a combination of full argument and mood; e.g. "If Plato is alive, he breathes ; but the first is true, therefore the second is true." This mode of argument was introduced in order that when dealing with long complex arguments we should not have to repeat the minor premiss, if it be long, and then state the conclusion, but may arrive at the conclusion as concisely as possible : if A, then B. Of arguments some are conclusive, others inconclusive. Inconclusive are such that the contradictory of the conclusion is not incompatible with combina-