There is nothing positively opposed to all this in the author's text: indeed he must be considered to have meant this, when he said, that by means of substituting one name for another, a predication marks the order of our sensations and ideas. The omission consists in not remarking that what is distinctively signified by a predication, as such, is Belief in a certain order of sensations or ideas. And when this has been said, the Hobbian addition, that it does so by declaring the predicate to be a name of everything of which the subject is a name, may be omitted as surplusage, and as diverting the mind from the essential features of the case. Predication may thus be defined, a form of speech which expresses a belief that a certain coexistence or sequence of sensations or ideas, did, does, or, under certain conditions, would take place: and the reverse of this when the predication is negative.--_Ed._]
{ 162} For the more complete elucidation of this important part of the business of Naming, it is necessary to { 163} remark, that Logicians have classed Predications, under five heads; 1st, when the _Genus_ is predicated, { 164} of any subject; 2dly, when the _Species_ is predicated; 3dly, when the _Specific Difference_ is predicated; 4thly, { 165} when a _Property_ is predicated; 5thly, when an _Accident_ is predicated. These five classes of names, the things capable of being predicated, are named PREDICABLES. The five Predicables, in Latin, the language in which they are commonly expressed, are named _Genus_, _Species_, _Differentia_, _Proprium_, _Accidens_.
We have already seen, perhaps at sufficient length, the manner in which, and the end for which, the Genus, and the Species are predicated of any subject. It is, that the more comprehensive name, may be substituted for the less comprehensive; so that each of our marks may answer the purpose of marking, to as great an extent as possible. In this manner we substitute the word _man_, for example, for the word _Thomas_, when we predicate the Species of the individual, in the proposition, "Thomas is a man;" the word _animal_, for the word _man_, when we predicate the Genus of the Species, in the proposition, "man, is an animal."[49]