The history of philosophy, in eight parts by Thomas Stanley.

CHAP. V

Of Apodeictick (or demonstrative) Syllogisme.

a 1.1 ALL discursive knowledge is made by a praenotion of the things themselves whereof we discourse; for ratiocination is not concerning things unknown. Demonstration is a discursive

knowledge, and therefore requireth three praecognitions. First, that the subject is, and what it is in a rude confused manner. Secondly, what the praedicate is, and what it signifieth. Thirdly, that the principles are true.

b 1.2 To know is to understand that a thing is, that this is cause thereof, and that it cannot be otherwise. Demonstration is a sci∣entifick Syllogisme. Demonstrative Science is from true, first, im∣mediate, more known, causes of the conclusion. First, as having none precedent, and being adaequate to, and convertible with the effect. Immediate or consectaneous, as having no terme be∣twixt to joyne them. More known, as being praensises to the con∣clusion, not to be demonstrated by any thing.

c 1.3 Demonstrative Science is of a thing necessary, whence the de∣monstration it selfe consists of necessary propositions; which necessity requireth explication of that which is praedicated, of all by it selfe, and which is universall.

Of all, is that which is attributed to every one and at all times, as a living creature to man.

By it selfe, as being of essence, proper, competible perse, and competible to it selfe, for it selfe.

An universall attribute is that which is in every one by it selfe, in as much as it is it selfe.

d 1.4 Demonstration is of conclusions of eternall truth, for they are universall propositions; whence it followeth, that neither de∣monstration nor Science are of perishable things; neither are de∣finitions of such, which are the principles of demonstration.

That there is demonstration, it is not necessary to have re∣course to Plato's Idaeas, separate from singulars; it is enough that there are common natures which are in singulars, and are prae∣dicated of them.

e 1.5 It is one thing to know that a thing is so, another to know why it is so. Hence there are two kinds of demonstration, 〈 in non-Latin alphabet 〉〈 in non-Latin alphabet 〉, and 〈 in non-Latin alphabet 〉〈 in non-Latin alphabet 〉, the first is the true and most perfect, of which hitherto.

f 1.6 The other kinde of demonstration, viz. 〈 in non-Latin alphabet 〉〈 in non-Latin alphabet 〉, is more im∣perfect; it is made two waies in the same Science: First, when the cause is demonstrated by the effect thus, Starres which do not twinkle are nearest to the earth; but, the Planets do not twinkle, therefore they are nearest to the earth. Secondly, when the effect is proved by a cause remote, and not reciprocall, or by an effect of the remote cause; as this, Every thing that breatheth is a living creature; but no Wall breaths, therefore no Wall is a living creature.

To know 〈 in non-Latin alphabet 〉〈 in non-Latin alphabet 〉, is proper to subalternat principle Sciences, as Geometry and Arithmetick, which contemplate the first proper causes; to know 〈 in non-Latin alphabet 〉〈 in non-Latin alphabet 〉, is of the subalternate and inferiour, as Op∣tick and Musick.

g 1.7 Of all figures, the first is most accommodate to knowledge, for that only concludes with an universall affirmative, and

therefore in that only is a demonstrative 〈 in non-Latin alphabet 〉〈 in non-Latin alphabet 〉.

h 1.8 Thus far concerning Science; the opposite to Science is Igno∣rance, which is two-fold: One of pure negation, as when a boy or ignorant fellow knowes not that the Sun is greater then the Earth, because he is ignorant of Astrologie. The other, of depra∣ved disposition, as when an Astrologer or ignorant Optick be∣lieves, that things are as they seem: this is errour, which erro∣neous ignorance is in false propositions, or in a Syllogisme through a false medium.

Defect of sense causeth ignorance of pure negation, for if any sense be wanting, it is necessary, that some science of sensibles be likewise wanting; for, we learn all things either by induction or demonstration. Induction is made of singulars perceived by sense. Demonstration is of universals, which are declared by induction; wherefore the beginning of Science is from singulars, which are sensibles. Hence it is impossible for a man born blinde to have the Science of colours. Yet no science is next and immediately from sense, for sense is of singulars, which are here and now; but sci∣ence and demonstration is of universals, which are every where and ever, not subject to sense. Yet, sense conduceth to science and demonstration, for as much as an universall is collected from particulars, known by sense.

Notes

• a 1.1

  Analyt. pos••er. lib▪ 1. cap. 1.
• b 1.2

  Cap. 2.
• c 1.3

  Cap. 4.
• d 1.4

  Cap. 8.
• e 1.5

  Cap. 11.
• f 1.6

  Cap. 13.
• g 1.7

  Cap. 14.
• h 1.8

  Cap. 15. &c.