El juego de la lógica y otros escritos

Excerpt: ...x, and some are not-x. 12. All x are y, and all not-y are not-x. See pp. 62, 3 Taking "nations" as Universe; x="civilised"; y="warlike"; 13. No uncivilised nation is warlike. 14. All unwarlike nations are uncivilised. 15. Some nations are unwarlike. 16. All warlike nations are civilised, and all civilised nations are warlike. 17. No nation is uncivilised. __________ Taking "crocodiles" as Universe; x="hungry"; and y="amiable"; 18. All hungry crocodiles are unamiable. 19. No crocodiles are amiable when hungry. 20. Some crocodiles, when not hungry, are amiable; but some are not. 21. No crocodiles are amiable, and some are hungry. 22. All crocodiles, when not hungry, are amiable; and all unamiable crocodiles are hungry. 23. Some hungry crocodiles are amiable, and some that are not hungry are unamiable. See pp. 63, 4 5. Smaller Diagram. Symbols to be interpreted. __________ ------ x -y--y'- x' ------ __________ ---- ---- 1. ---- 2. ---- 1 0 ---- ---- ---- ---- 1 3. ---- 4. ---- 0 0 0 ---- ---- __________ Taking "houses" as Universe; x="built of brick"; and y="two-storied"; interpret ---- ---- 0 5. ---- 6. ---- 0 - ---- ---- ---- ---- 0 7. ---- 8. ----...… (more)