Organon (Owen)/The Posterior Analytics/Book 2

Chap. 1. That the subjects of Scientific Investigation are four.
 * 1.1. Subjects of investigation: the that; the why; the if; and the what.  A thing is .  Instances.

Chap. 2. That all Investigation has reference to the Discovery of the Middle Term.
 * 2.1. The former four investigations may be reduced to two, concerning the middle term, if there be one, and what it is.
 * 2.2. The middle is that which expresses the cause why the major is predicated of the minor.
 * 2.3. We do not investigate the middle, if the thing itself, and its cause, fall within the cognizance of our senses.

Chap. 3. Upon the Difference between Demonstration and Definition.
 * 3.1. We cannot know by definition every subject capable of demonstration.
 * 3.2. Nor by demonstration all those which are capable of definition.
 * 3.3. In fact, nothing capable of definition admits demonstration.
 * 3.4. One part of a definition is not predicated of another.
 * 3.5. Recapitulation.

Chap. 4. That the Definition of a thing cannot be demonstrated.
 * 4.1. In order to collect by a syllogism what a thing is, the middle term ought to express the definition.
 * 4.2. A twofold consideration.
 * 4.3. He who proves the definition by a syllogism begs the question.

Chap. 5. That there is no Conclusion by Divisions proved.
 * 5.1. That the method by division is inconclusive.
 * 5.2. The same reasoning good in long or short definition.
 * 5.3. A rule applied for divisional definition.
 * 5.4. By constant division, when a perfect definition is arrived at, we are said to arrive at the individual.

Chap. 6. Case of one Proposition defining the Definition itself.
 * 6.1. It is proved that there is no demonstration of the definition, neither if one proposition defines the definition itself.
 * 6.2. Nor by any other hypothetical syllogism.

Chap. 7. That what a thung us can neither be known by Demonstration nor by Definition.
 * 7.1. An inquiry into the method of concluding definition. Objections.
 * 7.2.
 * 7.3. "Esse" is not the substance to any thing.
 * 7.4. Error of present modes.
 * 7.5.
 * 7.6. Recapitulation. It is proved that we can know "Quid res sit" neither by definition nor by demonstration.

Chap. 8. Of the logical Syllogism of what a thing is.
 * 8.1. Questions propounded for consideration.
 * 8.2. The logical syllogism "de eo, quid sit." The "why" and the "that" sometimes simultaneously known.  The "if" sometimes known.
 * 8.3. Of what a thing is, there is neither a syllogism nor demonstration, but it is manifested by both. Cf. ch. 3.

Chap. 9. Of certain Natures or Principles incapable of Demonstration.
 * 9.1. A two-fold division of things—the method used in each.

Chap. 10. Upon Definition and its kinds.
 * 10.1. Definition either explains the name of a thing;
 * 10.2. Or shows its cause. A distinction drawn.
 * 10.3. Brief summary—three forms of definition.

Chap. 11. Of Causes and their Demonstration.
 * 11.1. Causes of things are four which are all expressed by the middle term.
 * 11.2. The same thing may sometimes possess two causes.
 * 11.3. Necessity is two-fold; instances. Cf. Rhet. i. 11.

Chap. 12. Upon the causes of the Present, Past, and Future.
 * 12.1. Identity of cause.
 * 12.2. Causes and effects properly simultaneous—an inquiry into causes of things not simultaneous.
 * 12.3. The posterior not collected from the prior.
 * 12.4. Medium must be simultaneous with those of which it is the medium.
 * 12.5. In the cases of past and futures, some principle or first must be taken.
 * 12.6. Things generated in a circle must have a similar demonstration.
 * 12.7. Of things which are not universally, but usually, the principles should be non-necessary, but for the most part true.

Chap. 13. Upon the Method of investigating Definition.
 * 13.1. Division of things quoad extension.
 * 13.2. For the attainment of definition those to be taken, each of which is of wider extension than, but all together equal to, the thing to be defined.
 * 13.3. Method of dividing the genus.
 * 13.4. Differential division useful in the investigation of definition.
 * 13.5. It is not requisite that he who defines should know all other subjects from which he distinguishes the thing defined.
 * 13.6. A division into opposite members, as of animal into rational and irrational.
 * 13.7. Three things to be attended to, in divisional definition—how to effect these.
 * 13.8. The summum genus assumed in the definition.
 * 13.9. Method to be applied in the case of several species with something common.
 * 13.10. The especially universal most difficult to be defined.

Chap. 14. Rules for Problems.
 * 14.1. Need of division for rightly appropriating problems to each science.
 * 14.2. Also of investigating that which is inherent in the singulars as something common.
 * 14.3. Selection.

Chap. 15. Of Identical Problems.
 * 15.1. Problems are identical which have either the same middle term, or of which the one is subjected to the other.

Chap. 16. Of Causes and Effects.
 * 16.1. Solution of a difficulty—the middle term should always express the cause of the inference.
 * 16.2. There is only one cause of one and the same thing, from which it is inferred.

Chap. 17. Extension of the same subject.
 * 17.1. If the same thing is predicated of many, except there is an accidental demonstration, it must be shown from the same cause. If the conclusion is equivocal, the middle term will be so.  Cf. An. Post. i. 13.
 * 17.2. The major term ought to equal the minor in extent, although it ought to exceed the individuals comprehended.
 * 17.3. If the same is predicated of things differing in species, it can be demonstrated by diverse middle terms.

Chap. 18. Observation upon Cause to Singulars.
 * 18.1. The middle term ought to be the nearest to the singular to which it is cause.

Chap. 19. Upon the Method and Habit necessary to the ascertainment of Principles.
 * 19.1. Of the necessity and method of obtaining principles of science—certain questions relative to habits solved.
 * 19.2. Animals possess sensible perception.
 * 19.3. In what way we arrive at certain art or science from singulars subjected to the senses.
 * 19.4. Intellect alone conversant with, and itself the principle of science. All science through demonstration knows the objects of science.

