CHAPTER XXX.

CLASSIFICATION.

1. Classification 673

2. Classification involving Induction 675

3. Multiplicity of Modes of Classification 677

4. Natural and Artificial Systems of Classification 679

5. Correlation of Properties 681

6. Classification in Crystallography 685

7. Classification an Inverse and Tentative Operation 689

8. Symbolic Statement of the Theory of Classification 692

9. Bifurcate Classification 694

10. The Five Predicates 698

11. Summum Genus and Infima Species 701

12. The Tree of Porphyry 702

13. Does Abstraction imply Generalisation? 704

14. Discovery of Marks or Characteristics 708

15. Diagnostic Systems of Classification 710

16. Index Classifications 714

17. Classification in the Biological Sciences 718

18. Classification by Types 722

19. Natural Genera and Species 724

20. Unique or Exceptional Objects 728

21. Limits of Classification 730

BOOK VI.