An introduction to the art of logick composed for the use of English schools, and all such who having no opportunity of being instructed in the Latine tongue ... / by John Newton ...

CHAP. XVI. Of the Topicks from Genus and Spe∣cies.

TOpically Genus and Species are not al∣waies taken as in the predicables: for here Genus is every essential predicate; whe∣ther it be a Genus, properly called the predi∣cate of some species or individual: as animal is spoken of man, or of Socrates; or a spe∣cies spoken of individuals, as man of Socrates; or whether a Generical or specifical difference be spoken of the inferiour Species, which it doth constitute; as, sensibility of man; ratio∣nality of Socrates.

In like manner by Species here, we do not only understand that which is properly so called, which is immediately under his Ge∣nus, but a specifical difference, and also an in∣dividual it self; and whatsoever is subjected to something superiour, in that particular in which it is subjected, is called by the name of Species.

The Canons or Rules of Genus and Spe∣cies, are

• 1. If the Genus be taken away, the Species

• is taken away also; as, if there be not an Ani∣mal, there is neither man nor beast, nor rea∣sonable creature.
• 2. The Species being granted, the Genus is also granted; as, if there be a man or some∣thing that is rational, there is an animal. These rules hold alwaies.
• 3. What doth or doth not agree to the Genus, doth also agree or not agree to the Species; as, if an animal be sensible, a man is so; if it be not incorporeal, neither is a man. This rule fail∣leth 1. In a material or simple supposition, for neither is man a Genus, because there is an animal, or not a Species, because there is not an animal. 2. In those things which do agree or not agree in part only and not universally; as, neither is a man irrational because some animal is so, or not rational because some ani∣mal is not rational.
• 4. What doth or doth not agree to a Species, doth or doth not agree unto its Genus. This must be explained two waies. 1. What doth or doth not agree to any Species, doth or doth not agree to its Genus in part; thus are Syllogisms in the third figure; as, if man be rational, or not fourfooted, certainly some a∣nimal is rational, and some animal hath not four feet. 2. What doth or doth not agree to all the Species, doth or doth not agree to all

• the Genus: hence inductions are formed; as, if a man, a horse &c. be sensible, or are not immortal; certainly every animal is sensible, and no animal is immortal.