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Free logic

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2805: 650:, which neatly formalizes Quine's dictum. So, Lambert argues, to reject his construction of free logic requires you to reject Quine's philosophy, which requires some argument and also means that whatever logic you develop is always accompanied by the stipulation that you must reject Quine to accept the logic. Likewise, if you reject Quine then you must reject free logic. This amounts to the contribution that free logic makes to ontology. 510:
wrote in 1967: "In fact, one may regard free logic... literally as a theory about singular existence, in the sense that it lays down certain minimum conditions for that concept." The question that concerned the rest of his paper was then a description of the theory, and to inquire whether it gives a
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Informally, if F is '=y', G is 'is Pegasus', and we substitute 'Pegasus' for y, then (4) appears to allow us to infer from 'everything identical with Pegasus is Pegasus' that something is identical with Pegasus. The problem comes from substituting nondesignating constants for variables: in fact, we
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The point of free logic, though, is to have a formalism that implies no particular ontology, but that merely makes an interpretation of Quine both formally possible and simple. An advantage of this is that formalizing theories of singular existence in free logic brings out their implications for
526:. He criticizes this approach because it puts too much ideology into a logic, which is supposed to be philosophically neutral. Rather, he points out, not only does free logic provide for Quine's criterion—it even proves it! This is done by brute force, though, since he takes as axioms 325: 592: 167: 483: 407: 648: 225: 103: 241: 518:
so vigorously defended a form of logic that only accommodates his famous dictum, "To be is to be the value of a variable," when the logic is supplemented with
335:, since there are no nondesignating constants. Classically, ∃x(x=y) is deducible from the open equality axiom y=y by particularization (i.e. (3) above). 1184: 1859: 1942: 1083: 529: 110: 420: 345: 2256: 597: 2414: 1202: 174: 2269: 1592: 409:, where E! is an existence predicate (in some but not all formulations of free logic, E!t can be defined as ∃y(y=t)) 1053: 2274: 2264: 2001: 1854: 1207: 1198: 70: 2410: 995: 740: 1752: 2507: 2251: 1076: 1812: 1505: 1246: 2768: 2470: 2233: 2228: 2053: 1474: 1158: 36: 2763: 2546: 2463: 2176: 2107: 1984: 1226: 231: 2829: 2688: 2514: 2200: 1834: 1433: 708: 2566: 2561: 2171: 1910: 1839: 1168: 1069: 2495: 2085: 1479: 1447: 1138: 414: 2785: 2734: 2631: 2129: 2090: 1567: 1212: 1241: 2626: 2556: 2095: 1947: 1930: 1653: 1133: 32: 2458: 2435: 2396: 2282: 2223: 1869: 1789: 1633: 1577: 1190: 515: 713:. Metaphysics Research Lab, Stanford University – via Stanford Encyclopedia of Philosophy. 2748: 2475: 2453: 2420: 2313: 2159: 2144: 2117: 2068: 1952: 1887: 1712: 1678: 1673: 1547: 1378: 1355: 687: 682: 523: 2678: 2531: 2323: 2041: 1777: 1683: 1542: 1527: 1408: 1383: 320:{\displaystyle \forall x(Fx\rightarrow Gx)\land \exists xFx\rightarrow \exists x(Fx\land Gx)} 2651: 2613: 2490: 2294: 2134: 2058: 2036: 1864: 1822: 1721: 1688: 1552: 1340: 1251: 677: 8: 2780: 2671: 2656: 2636: 2593: 2480: 2430: 2356: 2301: 2238: 2031: 2026: 1974: 1742: 1731: 1403: 1303: 1231: 1222: 1218: 1153: 1148: 60: 2809: 2578: 2541: 2526: 2519: 2502: 2306: 2288: 2154: 2080: 2063: 2016: 1829: 1738: 1572: 1557: 1517: 1469: 1454: 1442: 1398: 1373: 1143: 1092: 961: 853: 814: 806: 729: 28: 1762: 2804: 2744: 2551: 2361: 2351: 2243: 2124: 1959: 1935: 1716: 1700: 1605: 1582: 1459: 1428: 1393: 1288: 1123: 991: 736: 332: 818: 2758: 2753: 2646: 2603: 2425: 2386: 2381: 2366: 2192: 2149: 2046: 1844: 1794: 1368: 1330: 953: 920: 887: 845: 798: 655: 519: 2739: 2729: 2683: 2666: 2621: 2583: 2485: 2405: 2212: 2139: 2112: 2100: 2006: 1920: 1894: 1849: 1817: 1618: 1420: 1363: 1313: 1278: 1236: 1048: 1044: 756: 724: 672: 492: 56: 2724: 2703: 2661: 2641: 2536: 2391: 1989: 1979: 1969: 1964: 1898: 1772: 1648: 1537: 1532: 1510: 1111: 925: 892: 413:
Similar modifications are made to other theorems with existential import (e.g.
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there are theorems that clearly presuppose that there is something in the
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Free logics: Their foundations, character, and some applications thereof.
778:. Perspectives in Analytical Philosophy 11. Berlin–New York: de Gruyter. 1638: 1493: 1270: 965: 857: 810: 789:
Hailperin, Theodore (1957). "A Theory of Restricted Quantification I".
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and George Nahknikian, which is that to exist is to be self-identical.
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easy analysis. Lambert takes the example of the theory proposed by
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presuppositions than classical logic. Free logics may allow for
587:{\displaystyle \exists xFx\rightarrow (\exists x(E!x\land Fx))} 162:{\displaystyle \forall x\forall rA(x)\Rightarrow \forall rA(r)} 478:{\displaystyle A(r)\rightarrow (E!r\rightarrow \exists xA(x))} 1915: 1261: 1106: 776:
Meinongian Logic. The Semantics of Existence and Nonexistence
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Nonexistent Objects – The Stanford Encyclopedia of Philosophy
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necessary and sufficient condition for existence statements.
488: 402:{\displaystyle \forall xA\rightarrow (E!t\rightarrow A(t/x))} 24: 761:
Abstract Objects. An Introduction to Axiomatic Metaphysics
643:{\displaystyle Fy\rightarrow (E!y\rightarrow \exists xFx)} 35:
that do not denote any object. Free logics may also allow
834:"Existential Presuppositions and Existential Commitments" 707:
Reicher, Maria (1 January 2016). Zalta, Edward N. (ed.).
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of free-logic are given by Theodore Hailperin (1957),
220:{\displaystyle \forall rA(r)\Rightarrow \exists xA(x)} 600: 532: 423: 348: 244: 177: 113: 73: 63:. Consider the following classically valid theorems. 909:"Objects and existence: Reflections on free logic" 728: 642: 586: 477: 401: 319: 219: 161: 97: 2821: 939: 755: 723: 98:{\displaystyle \forall xA\Rightarrow \exists xA} 773: 1004:———, 2001, "Free Logics," in Goble, Lou, ed., 982: 940:Nakhnikian, George; Salmon, Wesley C. (1957). 43:. A free logic with the latter property is an 1077: 1028:Morscher, Edgar, and Hieke, Alexander, 2001. 331:cannot do this in standard formulations of 1269: 1084: 1070: 1006:The Blackwell Guide to Philosophical Logic 906: 499:(1967), and Richard L. Mendelsohn (1989). 924: 891: 876:"Free logic and the concept of existence" 869: 867: 788: 1021:Philosophical applications of free logic 831: 873: 706: 2822: 1091: 864: 1065: 735:. New Haven: Yale University Press. 338:In free logic, (1) is replaced with 1054:Stanford Encyclopedia of Philosophy 234:which exhibits the same feature is 13: 913:Notre Dame Journal of Formal Logic 880:Notre Dame Journal of Formal Logic 625: 551: 533: 454: 349: 290: 275: 245: 199: 178: 141: 120: 114: 86: 74: 14: 2841: 1036: 502: 2803: 1042: 514:Lambert notes the irony in that 230:A valid scheme in the theory of 907:Mendelsohn, Richard L. (1989). 933: 900: 825: 782: 767: 749: 717: 700: 637: 622: 610: 607: 581: 578: 557: 548: 545: 472: 469: 463: 451: 439: 436: 433: 427: 396: 393: 379: 373: 361: 358: 314: 296: 287: 269: 260: 251: 214: 208: 196: 193: 187: 156: 150: 138: 135: 129: 83: 50: 1: 2764:History of mathematical logic 976: 791:The Journal of Symbolic Logic 2689:Primitive recursive function 7: 988:Free logic: Selected essays 661: 10: 2846: 1753:Schröder–Bernstein theorem 1480:Monadic predicate calculus 1139:Foundations of mathematics 415:existential generalization 2799: 2786:Philosophy of mathematics 2735:Automated theorem proving 2717: 2612: 2444: 2337: 2189: 1906: 1882: 1860:Von Neumann–Bernays–Gödel 1805: 1699: 1603: 1501: 1492: 1419: 1354: 1260: 1182: 1099: 1030:New essays in free logic. 1015:Sankt Augustin: Academia. 990:. Cambridge Univ. Press. 942:""Exists" as a Predicate" 838:The Journal of Philosophy 946:The Philosophical Review 926:10.1305/ndjfl/1093635243 893:10.1305/ndjfl/1093956251 832:Hintikka, Jaako (1959). 774:Jacquette, Dale (1996). 693: 2436:Self-verifying theories 2257:Tarski's axiomatization 1208:Tarski's undefinability 1203:incompleteness theorems 874:Lambert, Karel (1967). 516:Willard Van Orman Quine 2810:Mathematics portal 2421:Proof of impossibility 2069:propositional variable 1379:Propositional calculus 688:Table of logic symbols 683:Triangle of opposition 644: 588: 479: 403: 321: 221: 163: 99: 2679:Kolmogorov complexity 2632:Computably enumerable 2532:Model complete theory 2324:Principia Mathematica 1384:Propositional formula 1213:Banach–Tarski paradox 645: 589: 480: 404: 322: 222: 164: 100: 2627:Church–Turing thesis 2614:Computability theory 1823:continuum hypothesis 1341:Square of opposition 1199:Gödel's completeness 763:. Dordrecht: Reidel. 678:Square of opposition 598: 530: 421: 346: 242: 175: 111: 71: 2830:Non-classical logic 2781:Mathematical object 2672:P versus NP problem 2637:Computable function 2431:Reverse mathematics 2357:Logical consequence 2234:primitive recursive 2229:elementary function 2002:Free/bound variable 1855:Tarski–Grothendieck 1374:Logical connectives 1304:Logical equivalence 1154:Logical consequence 1025:Oxford Univ. Press. 731:Nonexistent Objects 61:domain of discourse 2579:Transfer principle 2542:Semantics of logic 2527:Categorical theory 2503:Non-standard model 2017:Logical connective 1144:Information theory 1093:Mathematical logic 1032:Dordrecht: Kluwer. 640: 584: 524:description theory 475: 399: 317: 217: 159: 95: 2817: 2816: 2749:Abstract category 2552:Theories of truth 2362:Rule of inference 2352:Natural deduction 2333: 2332: 1878: 1877: 1583:Cartesian product 1488: 1487: 1394:Many-valued logic 1369:Boolean functions 1252:Russell's paradox 1227:diagonal argument 1124:First-order logic 333:first-order logic 2837: 2808: 2807: 2759:History of logic 2754:Category of sets 2647:Decision problem 2426:Ordinal analysis 2367:Sequent calculus 2265:Boolean algebras 2205: 2204: 2179: 2150:logical/constant 1904: 1903: 1890: 1813:Zermelo–Fraenkel 1564:Set operations: 1499: 1498: 1436: 1267: 1266: 1247:Löwenheim–Skolem 1134:Formal semantics 1086: 1079: 1072: 1063: 1062: 1058: 1049:Zalta, Edward N. 1001: 970: 969: 937: 931: 930: 928: 904: 898: 897: 895: 871: 862: 861: 829: 823: 822: 786: 780: 779: 771: 765: 764: 757:Zalta, Edward N. 753: 747: 746: 734: 725:Parsons, Terence 721: 715: 714: 704: 656:Wesley C. Salmon 649: 647: 646: 641: 593: 591: 590: 585: 484: 482: 481: 476: 408: 406: 405: 400: 389: 326: 324: 323: 318: 226: 224: 223: 218: 168: 166: 165: 160: 104: 102: 101: 96: 2845: 2844: 2840: 2839: 2838: 2836: 2835: 2834: 2820: 2819: 2818: 2813: 2802: 2795: 2740:Category theory 2730:Algebraic logic 2713: 2684:Lambda calculus 2622:Church encoding 2608: 2584:Truth predicate 2440: 2406:Complete theory 2329: 2198: 2194: 2190: 2185: 2177: 1897: and  1893: 1888: 1874: 1850:New Foundations 1818:axiom of choice 1801: 1763:Gödel numbering 1703: and  1695: 1599: 1484: 1434: 1415: 1364:Boolean algebra 1350: 1314:Equiconsistency 1279:Classical logic 1256: 1237:Halting problem 1225: and  1201: and  1189: and  1188: 1183:Theorems ( 1178: 1095: 1090: 1039: 1018:———, ed. 1991. 998: 979: 974: 973: 958:10.2307/2182749 938: 934: 905: 901: 872: 865: 850:10.2307/2021988 830: 826: 803:10.2307/2964055 787: 783: 772: 768: 754: 750: 743: 722: 718: 705: 701: 696: 673:Logical hexagon 664: 599: 596: 595: 531: 528: 527: 522:assumptions of 505: 493:Jaakko Hintikka 489:Axiomatizations 422: 419: 418: 385: 347: 344: 343: 243: 240: 239: 176: 173: 172: 112: 109: 108: 72: 69: 68: 57:classical logic 53: 45:inclusive logic 17: 12: 11: 5: 2843: 2833: 2832: 2815: 2814: 2800: 2797: 2796: 2794: 2793: 2788: 2783: 2778: 2773: 2772: 2771: 2761: 2756: 2751: 2742: 2737: 2732: 2727: 2725:Abstract logic 2721: 2719: 2715: 2714: 2712: 2711: 2706: 2704:Turing machine 2701: 2696: 2691: 2686: 2681: 2676: 2675: 2674: 2669: 2664: 2659: 2654: 2644: 2642:Computable set 2639: 2634: 2629: 2624: 2618: 2616: 2610: 2609: 2607: 2606: 2601: 2596: 2591: 2586: 2581: 2576: 2571: 2570: 2569: 2564: 2559: 2549: 2544: 2539: 2537:Satisfiability 2534: 2529: 2524: 2523: 2522: 2512: 2511: 2510: 2500: 2499: 2498: 2493: 2488: 2483: 2478: 2468: 2467: 2466: 2461: 2454:Interpretation 2450: 2448: 2442: 2441: 2439: 2438: 2433: 2428: 2423: 2418: 2408: 2403: 2402: 2401: 2400: 2399: 2389: 2384: 2374: 2369: 2364: 2359: 2354: 2349: 2343: 2341: 2335: 2334: 2331: 2330: 2328: 2327: 2319: 2318: 2317: 2316: 2311: 2310: 2309: 2304: 2299: 2279: 2278: 2277: 2275:minimal axioms 2272: 2261: 2260: 2259: 2248: 2247: 2246: 2241: 2236: 2231: 2226: 2221: 2208: 2206: 2187: 2186: 2184: 2183: 2182: 2181: 2169: 2164: 2163: 2162: 2157: 2152: 2147: 2137: 2132: 2127: 2122: 2121: 2120: 2115: 2105: 2104: 2103: 2098: 2093: 2088: 2078: 2073: 2072: 2071: 2066: 2061: 2051: 2050: 2049: 2044: 2039: 2034: 2029: 2024: 2014: 2009: 2004: 1999: 1998: 1997: 1992: 1987: 1982: 1972: 1967: 1965:Formation rule 1962: 1957: 1956: 1955: 1950: 1940: 1939: 1938: 1928: 1923: 1918: 1913: 1907: 1901: 1884:Formal systems 1880: 1879: 1876: 1875: 1873: 1872: 1867: 1862: 1857: 1852: 1847: 1842: 1837: 1832: 1827: 1826: 1825: 1820: 1809: 1807: 1803: 1802: 1800: 1799: 1798: 1797: 1787: 1782: 1781: 1780: 1773:Large cardinal 1770: 1765: 1760: 1755: 1750: 1736: 1735: 1734: 1729: 1724: 1709: 1707: 1697: 1696: 1694: 1693: 1692: 1691: 1686: 1681: 1671: 1666: 1661: 1656: 1651: 1646: 1641: 1636: 1631: 1626: 1621: 1616: 1610: 1608: 1601: 1600: 1598: 1597: 1596: 1595: 1590: 1585: 1580: 1575: 1570: 1562: 1561: 1560: 1555: 1545: 1540: 1538:Extensionality 1535: 1533:Ordinal number 1530: 1520: 1515: 1514: 1513: 1502: 1496: 1490: 1489: 1486: 1485: 1483: 1482: 1477: 1472: 1467: 1462: 1457: 1452: 1451: 1450: 1440: 1439: 1438: 1425: 1423: 1417: 1416: 1414: 1413: 1412: 1411: 1406: 1401: 1391: 1386: 1381: 1376: 1371: 1366: 1360: 1358: 1352: 1351: 1349: 1348: 1343: 1338: 1333: 1328: 1323: 1318: 1317: 1316: 1306: 1301: 1296: 1291: 1286: 1281: 1275: 1273: 1264: 1258: 1257: 1255: 1254: 1249: 1244: 1239: 1234: 1229: 1217:Cantor's  1215: 1210: 1205: 1195: 1193: 1180: 1179: 1177: 1176: 1171: 1166: 1161: 1156: 1151: 1146: 1141: 1136: 1131: 1126: 1121: 1116: 1115: 1114: 1103: 1101: 1097: 1096: 1089: 1088: 1081: 1074: 1066: 1060: 1059: 1038: 1037:External links 1035: 1034: 1033: 1026: 1016: 1009: 1002: 996: 984:Lambert, Karel 978: 975: 972: 971: 952:(4): 535–542. 932: 899: 863: 844:(3): 125–137. 824: 781: 766: 748: 741: 716: 698: 697: 695: 692: 691: 690: 685: 680: 675: 670: 663: 660: 639: 636: 633: 630: 627: 624: 621: 618: 615: 612: 609: 606: 603: 583: 580: 577: 574: 571: 568: 565: 562: 559: 556: 553: 550: 547: 544: 541: 538: 535: 504: 503:Interpretation 501: 474: 471: 468: 465: 462: 459: 456: 453: 450: 447: 444: 441: 438: 435: 432: 429: 426: 411: 410: 398: 395: 392: 388: 384: 381: 378: 375: 372: 369: 366: 363: 360: 357: 354: 351: 328: 327: 316: 313: 310: 307: 304: 301: 298: 295: 292: 289: 286: 283: 280: 277: 274: 271: 268: 265: 262: 259: 256: 253: 250: 247: 228: 227: 216: 213: 210: 207: 204: 201: 198: 195: 192: 189: 186: 183: 180: 169: 158: 155: 152: 149: 146: 143: 140: 137: 134: 131: 128: 125: 122: 119: 116: 105: 94: 91: 88: 85: 82: 79: 76: 52: 49: 15: 9: 6: 4: 3: 2: 2842: 2831: 2828: 2827: 2825: 2812: 2811: 2806: 2798: 2792: 2789: 2787: 2784: 2782: 2779: 2777: 2774: 2770: 2767: 2766: 2765: 2762: 2760: 2757: 2755: 2752: 2750: 2746: 2743: 2741: 2738: 2736: 2733: 2731: 2728: 2726: 2723: 2722: 2720: 2716: 2710: 2707: 2705: 2702: 2700: 2699:Recursive set 2697: 2695: 2692: 2690: 2687: 2685: 2682: 2680: 2677: 2673: 2670: 2668: 2665: 2663: 2660: 2658: 2655: 2653: 2650: 2649: 2648: 2645: 2643: 2640: 2638: 2635: 2633: 2630: 2628: 2625: 2623: 2620: 2619: 2617: 2615: 2611: 2605: 2602: 2600: 2597: 2595: 2592: 2590: 2587: 2585: 2582: 2580: 2577: 2575: 2572: 2568: 2565: 2563: 2560: 2558: 2555: 2554: 2553: 2550: 2548: 2545: 2543: 2540: 2538: 2535: 2533: 2530: 2528: 2525: 2521: 2518: 2517: 2516: 2513: 2509: 2508:of arithmetic 2506: 2505: 2504: 2501: 2497: 2494: 2492: 2489: 2487: 2484: 2482: 2479: 2477: 2474: 2473: 2472: 2469: 2465: 2462: 2460: 2457: 2456: 2455: 2452: 2451: 2449: 2447: 2443: 2437: 2434: 2432: 2429: 2427: 2424: 2422: 2419: 2416: 2415:from ZFC 2412: 2409: 2407: 2404: 2398: 2395: 2394: 2393: 2390: 2388: 2385: 2383: 2380: 2379: 2378: 2375: 2373: 2370: 2368: 2365: 2363: 2360: 2358: 2355: 2353: 2350: 2348: 2345: 2344: 2342: 2340: 2336: 2326: 2325: 2321: 2320: 2315: 2314:non-Euclidean 2312: 2308: 2305: 2303: 2300: 2298: 2297: 2293: 2292: 2290: 2287: 2286: 2284: 2280: 2276: 2273: 2271: 2268: 2267: 2266: 2262: 2258: 2255: 2254: 2253: 2249: 2245: 2242: 2240: 2237: 2235: 2232: 2230: 2227: 2225: 2222: 2220: 2217: 2216: 2214: 2210: 2209: 2207: 2202: 2196: 2191:Example  2188: 2180: 2175: 2174: 2173: 2170: 2168: 2165: 2161: 2158: 2156: 2153: 2151: 2148: 2146: 2143: 2142: 2141: 2138: 2136: 2133: 2131: 2128: 2126: 2123: 2119: 2116: 2114: 2111: 2110: 2109: 2106: 2102: 2099: 2097: 2094: 2092: 2089: 2087: 2084: 2083: 2082: 2079: 2077: 2074: 2070: 2067: 2065: 2062: 2060: 2057: 2056: 2055: 2052: 2048: 2045: 2043: 2040: 2038: 2035: 2033: 2030: 2028: 2025: 2023: 2020: 2019: 2018: 2015: 2013: 2010: 2008: 2005: 2003: 2000: 1996: 1993: 1991: 1988: 1986: 1983: 1981: 1978: 1977: 1976: 1973: 1971: 1968: 1966: 1963: 1961: 1958: 1954: 1951: 1949: 1948:by definition 1946: 1945: 1944: 1941: 1937: 1934: 1933: 1932: 1929: 1927: 1924: 1922: 1919: 1917: 1914: 1912: 1909: 1908: 1905: 1902: 1900: 1896: 1891: 1885: 1881: 1871: 1868: 1866: 1863: 1861: 1858: 1856: 1853: 1851: 1848: 1846: 1843: 1841: 1838: 1836: 1835:Kripke–Platek 1833: 1831: 1828: 1824: 1821: 1819: 1816: 1815: 1814: 1811: 1810: 1808: 1804: 1796: 1793: 1792: 1791: 1788: 1786: 1783: 1779: 1776: 1775: 1774: 1771: 1769: 1766: 1764: 1761: 1759: 1756: 1754: 1751: 1748: 1744: 1740: 1737: 1733: 1730: 1728: 1725: 1723: 1720: 1719: 1718: 1714: 1711: 1710: 1708: 1706: 1702: 1698: 1690: 1687: 1685: 1682: 1680: 1679:constructible 1677: 1676: 1675: 1672: 1670: 1667: 1665: 1662: 1660: 1657: 1655: 1652: 1650: 1647: 1645: 1642: 1640: 1637: 1635: 1632: 1630: 1627: 1625: 1622: 1620: 1617: 1615: 1612: 1611: 1609: 1607: 1602: 1594: 1591: 1589: 1586: 1584: 1581: 1579: 1576: 1574: 1571: 1569: 1566: 1565: 1563: 1559: 1556: 1554: 1551: 1550: 1549: 1546: 1544: 1541: 1539: 1536: 1534: 1531: 1529: 1525: 1521: 1519: 1516: 1512: 1509: 1508: 1507: 1504: 1503: 1500: 1497: 1495: 1491: 1481: 1478: 1476: 1473: 1471: 1468: 1466: 1463: 1461: 1458: 1456: 1453: 1449: 1446: 1445: 1444: 1441: 1437: 1432: 1431: 1430: 1427: 1426: 1424: 1422: 1418: 1410: 1407: 1405: 1402: 1400: 1397: 1396: 1395: 1392: 1390: 1387: 1385: 1382: 1380: 1377: 1375: 1372: 1370: 1367: 1365: 1362: 1361: 1359: 1357: 1356:Propositional 1353: 1347: 1344: 1342: 1339: 1337: 1334: 1332: 1329: 1327: 1324: 1322: 1319: 1315: 1312: 1311: 1310: 1307: 1305: 1302: 1300: 1297: 1295: 1292: 1290: 1287: 1285: 1284:Logical truth 1282: 1280: 1277: 1276: 1274: 1272: 1268: 1265: 1263: 1259: 1253: 1250: 1248: 1245: 1243: 1240: 1238: 1235: 1233: 1230: 1228: 1224: 1220: 1216: 1214: 1211: 1209: 1206: 1204: 1200: 1197: 1196: 1194: 1192: 1186: 1181: 1175: 1172: 1170: 1167: 1165: 1162: 1160: 1157: 1155: 1152: 1150: 1147: 1145: 1142: 1140: 1137: 1135: 1132: 1130: 1127: 1125: 1122: 1120: 1117: 1113: 1110: 1109: 1108: 1105: 1104: 1102: 1098: 1094: 1087: 1082: 1080: 1075: 1073: 1068: 1067: 1064: 1056: 1055: 1050: 1046: 1041: 1040: 1031: 1027: 1024: 1022: 1017: 1014: 1010: 1007: 1003: 999: 997:9780511039195 993: 989: 985: 981: 980: 967: 963: 959: 955: 951: 947: 943: 936: 927: 922: 918: 914: 910: 903: 894: 889: 885: 881: 877: 870: 868: 859: 855: 851: 847: 843: 839: 835: 828: 820: 816: 812: 808: 804: 800: 796: 792: 785: 777: 770: 762: 758: 752: 744: 742:9780300024043 738: 733: 732: 726: 720: 712: 711: 703: 699: 689: 686: 684: 681: 679: 676: 674: 671: 669: 666: 665: 659: 657: 651: 634: 631: 628: 619: 616: 613: 604: 601: 575: 572: 569: 566: 563: 560: 554: 542: 539: 536: 525: 521: 517: 512: 509: 508:Karel Lambert 500: 498: 497:Karel Lambert 494: 490: 486: 466: 460: 457: 448: 445: 442: 430: 424: 416: 390: 386: 382: 376: 370: 367: 364: 355: 352: 341: 340: 339: 336: 334: 311: 308: 305: 302: 299: 293: 284: 281: 278: 272: 266: 263: 257: 254: 248: 237: 236: 235: 233: 211: 205: 202: 190: 184: 181: 170: 153: 147: 144: 132: 126: 123: 117: 106: 92: 89: 80: 77: 66: 65: 64: 62: 58: 48: 46: 42: 39:that have an 38: 34: 30: 26: 22: 16:Form of logic 2801: 2599:Ultraproduct 2446:Model theory 2411:Independence 2347:Formal proof 2339:Proof theory 2322: 2295: 2252:real numbers 2224:second-order 2135:Substitution 2012:Metalanguage 1953:conservative 1926:Axiom schema 1870:Constructive 1840:Morse–Kelley 1806:Set theories 1785:Aleph number 1778:inaccessible 1684:Grothendieck 1568:intersection 1464: 1455:Higher-order 1443:Second-order 1389:Truth tables 1346:Venn diagram 1129:Formal proof 1052: 1045:"Free logic" 1043:Nolt, John. 1029: 1019: 1012: 1008:. Blackwell. 1005: 987: 949: 945: 935: 916: 912: 902: 883: 879: 841: 837: 827: 797:(1): 19–35. 794: 790: 784: 775: 769: 760: 751: 730: 719: 709: 702: 668:Logical cube 652: 513: 506: 487: 412: 337: 329: 229: 54: 44: 41:empty domain 20: 18: 2709:Type theory 2657:undecidable 2589:Truth value 2476:equivalence 2155:non-logical 1768:Enumeration 1758:Isomorphism 1705:cardinality 1689:Von Neumann 1654:Ultrafilter 1619:Uncountable 1553:equivalence 1470:Quantifiers 1460:Fixed-point 1429:First-order 1309:Consistency 1294:Proposition 1271:Traditional 1242:Lindström's 1232:Compactness 1174:Type theory 1119:Cardinality 1011:———, 1997. 51:Explanation 29:existential 27:with fewer 2520:elementary 2213:arithmetic 2081:Quantifier 2059:functional 1931:Expression 1649:Transitive 1593:identities 1578:complement 1511:hereditary 1494:Set theory 977:References 520:Russellian 21:free logic 2791:Supertask 2694:Recursion 2652:decidable 2486:saturated 2464:of models 2387:deductive 2382:axiomatic 2302:Hilbert's 2289:Euclidean 2270:canonical 2193:axiomatic 2125:Signature 2054:Predicate 1943:Extension 1865:Ackermann 1790:Operation 1669:Universal 1659:Recursive 1634:Singleton 1629:Inhabited 1614:Countable 1604:Types of 1588:power set 1558:partition 1475:Predicate 1421:Predicate 1336:Syllogism 1326:Soundness 1299:Inference 1289:Tautology 1191:paradoxes 626:∃ 623:→ 608:→ 570:∧ 552:∃ 546:→ 534:∃ 455:∃ 452:→ 437:→ 374:→ 359:→ 350:∀ 306:∧ 291:∃ 288:→ 276:∃ 273:∧ 261:→ 246:∀ 200:∃ 197:⇒ 179:∀ 142:∀ 139:⇒ 121:∀ 115:∀ 87:∃ 84:⇒ 75:∀ 2824:Category 2776:Logicism 2769:timeline 2745:Concrete 2604:Validity 2574:T-schema 2567:Kripke's 2562:Tarski's 2557:semantic 2547:Strength 2496:submodel 2491:spectrum 2459:function 2307:Tarski's 2296:Elements 2283:geometry 2239:Robinson 2160:variable 2145:function 2118:spectrum 2108:Sentence 2064:variable 2007:Language 1960:Relation 1921:Automata 1911:Alphabet 1895:language 1749:-jection 1727:codomain 1713:Function 1674:Universe 1644:Infinite 1548:Relation 1331:Validity 1321:Argument 1219:theorem, 986:(2003). 819:34062434 759:(1983). 727:(1980). 662:See also 495:(1959), 417:becomes 232:equality 2718:Related 2515:Diagram 2413: ( 2392:Hilbert 2377:Systems 2372:Theorem 2250:of the 2195:systems 1975:Formula 1970:Grammar 1886: ( 1830:General 1543:Forcing 1528:Element 1448:Monadic 1223:paradox 1164:Theorem 1100:General 1051:(ed.). 966:2182749 886:(1–2). 858:2021988 811:2964055 2481:finite 2244:Skolem 2197:  2172:Theory 2140:Symbol 2130:String 2113:atomic 1990:ground 1985:closed 1980:atomic 1936:ground 1899:syntax 1795:binary 1722:domain 1639:Finite 1404:finite 1262:Logics 1221:  1169:Theory 994:  964:  856:  817:  809:  739:  37:models 2471:Model 2219:Peano 2076:Proof 1916:Arity 1845:Naive 1732:image 1664:Fuzzy 1624:Empty 1573:union 1518:Class 1159:Model 1149:Lemma 1107:Axiom 1047:. In 962:JSTOR 919:(4). 854:JSTOR 815:S2CID 807:JSTOR 694:Notes 33:terms 25:logic 23:is a 2594:Type 2397:list 2201:list 2178:list 2167:Term 2101:rank 1995:open 1889:list 1701:Maps 1606:sets 1465:Free 1435:list 1185:list 1112:list 992:ISBN 737:ISBN 594:and 342:1b. 2281:of 2263:of 2211:of 1743:Sur 1717:Map 1524:Ur- 1506:Set 954:doi 921:doi 888:doi 846:doi 799:doi 238:4. 171:3. 107:2. 67:1. 55:In 2826:: 2667:NP 2291:: 2285:: 2215:: 1892:), 1747:Bi 1739:In 960:. 950:66 948:. 944:. 917:30 915:. 911:. 882:. 878:. 866:^ 852:. 842:56 840:. 836:. 813:. 805:. 795:22 793:. 485:. 47:. 19:A 2747:/ 2662:P 2417:) 2203:) 2199:( 2096:∀ 2091:! 2086:∃ 2047:= 2042:↔ 2037:→ 2032:∧ 2027:√ 2022:ÂŹ 1745:/ 1741:/ 1715:/ 1526:) 1522:( 1409:∞ 1399:3 1187:) 1085:e 1078:t 1071:v 1057:. 1023:. 1000:. 968:. 956:: 929:. 923:: 896:. 890:: 884:8 860:. 848:: 821:. 801:: 745:. 638:) 635:x 632:F 629:x 620:y 617:! 614:E 611:( 605:y 602:F 582:) 579:) 576:x 573:F 567:x 564:! 561:E 558:( 555:x 549:( 543:x 540:F 537:x 473:) 470:) 467:x 464:( 461:A 458:x 449:r 446:! 443:E 440:( 434:) 431:r 428:( 425:A 397:) 394:) 391:x 387:/ 383:t 380:( 377:A 371:t 368:! 365:E 362:( 356:A 353:x 315:) 312:x 309:G 303:x 300:F 297:( 294:x 285:x 282:F 279:x 270:) 267:x 264:G 258:x 255:F 252:( 249:x 215:) 212:x 209:( 206:A 203:x 194:) 191:r 188:( 185:A 182:r 157:) 154:r 151:( 148:A 145:r 136:) 133:x 130:( 127:A 124:r 118:x 93:A 90:x 81:A 78:x

Index

logic
existential
terms
models
empty domain
classical logic
domain of discourse
equality
first-order logic
existential generalization
Axiomatizations
Jaakko Hintikka
Karel Lambert
Karel Lambert
Willard Van Orman Quine
Russellian
description theory
Wesley C. Salmon
Logical cube
Logical hexagon
Square of opposition
Triangle of opposition
Table of logic symbols
Nonexistent Objects – The Stanford Encyclopedia of Philosophy
Parsons, Terence
Nonexistent Objects
ISBN
9780300024043
Zalta, Edward N.
doi

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