the causes of this necessity are the first premises, i.e. the fact that the propositions from which the syllogism proceeds cannot be otherwise.
Now some things owe their necessity to something other than themselves; others do not, while they are the source of necessity in other things. Therefore the necessary in the primary and strict sense is the simple; for this does not admit of more states than one, so that it does not admit even of one state and another; for already it would admit of more than one. If, then, there are certain eternal and unmovable things, nothing compulsory or against their nature attaches to them.
Chapter 6
'One' means (1) that which is one by accident, (2) that which is one by its own nature, (1) Instances of the accidentally one are 'Coriscus' and 'musical', and 'musical Coriscus' (for it is the same thing to say 'Coriscus' and 'musical', and 'musical Coriscus'), and 'musical' and 'just', and 'musical Coriscus' and 'just Coriscus'. For all these are called one by accident, 'just' and 'musical' because they are accidents of one substance, 'musical ' and 'Coriscus' because the one is an accident of the other; and similarly in a sense 'musical Coriscus' is one with 'Coriscus', because one of the parts of the concept is an accident of the other, i.e. 'musical' is an accident of Coriscus; and 'musical Coriscus' is one with 'just Coriscus', because both have parts which are accidents of one and the same subject. The case is similar if the accident is predicated of a class or of any universal term, e.g. if one says that man is the same as 'musical man'; for this is either because 'musical' is an accident of man, which is one substance, or because both are accidents of some individual, e.g. Coriscus. Both, however, do not belong to him in the same way, but one doubtless as genus and in the substance, the other as a state or affection of the substance.
The things, then, that are called one by accident, are called so in this way. (2) Of things that are called one in virtue of their own nature some (a) are so called because they are continuous, e.g. a bundle is made one by a band, and pieces
