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Craig's theorem

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argued based on this that since all science's predictions are in the vocabulary of observation terms, the theoretical vocabulary of science is in principle eliminable. He himself raised two objections to this argument: 1) the new axioms of science are practically unmanageable, and 2) science uses
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argues that this argument is based on a misconception that the sole aim of science is successful prediction. He proposes that the main reason we need theoretical terms is that we wish to talk about theoretical entities (such as viruses, radio stars, and elementary particles).
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The proof above shows that for each recursively enumerable set of axioms there is a recursive set of axioms with the same deductive closure. A set of axioms is
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if there is a primitive recursive function that decides membership in the set. To obtain a primitive recursive axiomatization, instead of replacing a formula
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is in the original recursively enumerable set of axioms. It is possible for a primitive recursive function to parse an expression of form (*) to obtain
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Since each formula has finite length, it is checkable whether or not it is of the said form. If it is of the said form and consists of
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inductive reasoning and eliminating theoretical terms may alter the inductive relations between observational sentences.
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is a recursively axiomatizable theory and we divide its predicates into two disjoint sets
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is primitive recursive, it is possible for a primitive recursive function to verify that
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are recursively enumerable, and hence, based on Craig's theorem, axiomatizable.
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and then checking symbol-for-symbol whether the expressions are identical.
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lends itself according to the following informal reasoning. Each member of
766:{\displaystyle \underbrace {A_{i}\land \dots \land A_{i}} _{f(i)}} 48:
theorem, although both results are named after the same logician,
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be an enumeration of the axioms of a recursively enumerable set
689:{\displaystyle \underbrace {A_{i}\land \dots \land A_{i}} _{i}} 211:{\displaystyle \underbrace {A_{i}\land \dots \land A_{i}} _{i}} 545:. Again, it is checkable whether the conjunct is in fact 1074:". Bulletin of Symbolic Logic, vol. 18, no. 3 (2012). 1023: 1003: 976: 949: 929: 901: 877: 850: 823: 803: 783: 708: 640: 610: 578: 551: 524: 497: 470: 450: 382: 352: 325: 298: 278: 251: 227: 162: 132: 112: 66: 1036: 1009: 989: 962: 935: 907: 883: 863: 836: 809: 789: 765: 688: 623: 584: 572:by going through the enumeration of the axioms of 564: 537: 510: 483: 456: 433: 365: 338: 311: 284: 264: 233: 210: 145: 118: 98: 1072:Vaught's Theorem on Axiomatizability by a Scheme 126:of first-order formulas. Construct another set 44:. This result is not related to the well-known 292:are thus equivalent; the proof will show that 915:is indeed a computation history as required. 817:, returns a computation history showing that 319:is a recursive set. A decision procedure for 8: 1122:Theorems in the foundations of mathematics 1085:. "On Axiomatizability Within a System", 1028: 1022: 1002: 981: 975: 954: 948: 928: 900: 876: 855: 849: 828: 822: 802: 782: 748: 736: 717: 710: 707: 680: 668: 649: 642: 639: 615: 609: 577: 556: 550: 529: 523: 502: 496: 475: 469: 449: 422: 410: 391: 384: 381: 357: 351: 330: 324: 303: 297: 277: 256: 250: 226: 202: 190: 171: 164: 161: 137: 131: 111: 84: 71: 65: 1063: 1103:, Vol. 62, No. 10 (1965), pp. 251.260. 7: 1091:, Vol. 18, No. 1 (1953), pp. 30-32. 596:Primitive recursive axiomatizations 99:{\displaystyle A_{1},A_{2},\dots } 14: 491:if the (reoccurring) conjunct is 758: 752: 699:one instead replaces it with 1: 1088:The Journal of Symbolic Logic 40:is (primitively) recursively 1017:that are in the vocabulary 1138: 919:Philosophical implications 797:is a function that, given 221:for each positive integer 30:recursively enumerable set 1100:The Journal of Philosophy 997:, then those theorems of 518:; otherwise it is not in 56:Recursive axiomatization 1038: 1011: 991: 964: 937: 909: 885: 865: 838: 811: 791: 767: 690: 625: 586: 566: 539: 512: 485: 458: 435: 367: 340: 313: 286: 266: 235: 212: 147: 120: 100: 1097:. "Craig's Theorem", 1039: 1037:{\displaystyle V_{A}} 1012: 992: 990:{\displaystyle V_{B}} 965: 963:{\displaystyle V_{A}} 938: 910: 886: 866: 864:{\displaystyle A_{i}} 839: 837:{\displaystyle A_{i}} 812: 792: 768: 691: 626: 624:{\displaystyle A_{i}} 587: 567: 565:{\displaystyle A_{n}} 540: 538:{\displaystyle T^{*}} 513: 511:{\displaystyle A_{j}} 486: 484:{\displaystyle T^{*}} 459: 436: 368: 366:{\displaystyle T^{*}} 341: 339:{\displaystyle T^{*}} 314: 312:{\displaystyle T^{*}} 287: 267: 265:{\displaystyle T^{*}} 236: 213: 148: 146:{\displaystyle T^{*}} 121: 101: 1117:Computability theory 1021: 1001: 974: 947: 927: 899: 893:Kleene's T predicate 875: 848: 821: 801: 781: 706: 638: 608: 576: 549: 522: 495: 468: 464:conjuncts, it is in 448: 380: 350: 323: 296: 276: 249: 225: 160: 130: 110: 64: 38:first-order language 34:well-formed formulas 602:primitive recursive 46:Craig interpolation 1034: 1007: 987: 960: 933: 905: 881: 861: 834: 807: 787: 763: 762: 746: 686: 685: 678: 621: 582: 562: 535: 508: 481: 454: 431: 427: 420: 363: 336: 309: 282: 262: 243:deductive closures 231: 208: 207: 200: 143: 116: 96: 28:) states that any 18:mathematical logic 1010:{\displaystyle T} 936:{\displaystyle T} 908:{\displaystyle j} 884:{\displaystyle j} 810:{\displaystyle i} 790:{\displaystyle f} 711: 709: 643: 641: 585:{\displaystyle T} 457:{\displaystyle j} 385: 383: 285:{\displaystyle T} 234:{\displaystyle i} 165: 163: 119:{\displaystyle T} 1129: 1075: 1068: 1043: 1041: 1040: 1035: 1033: 1032: 1016: 1014: 1013: 1008: 996: 994: 993: 988: 986: 985: 969: 967: 966: 961: 959: 958: 942: 940: 939: 934: 914: 912: 911: 906: 891:. Then, because 890: 888: 887: 882: 870: 868: 867: 862: 860: 859: 843: 841: 840: 835: 833: 832: 816: 814: 813: 808: 796: 794: 793: 788: 772: 770: 769: 764: 761: 747: 742: 741: 740: 722: 721: 695: 693: 692: 687: 684: 679: 674: 673: 672: 654: 653: 630: 628: 627: 622: 620: 619: 591: 589: 588: 583: 571: 569: 568: 563: 561: 560: 544: 542: 541: 536: 534: 533: 517: 515: 514: 509: 507: 506: 490: 488: 487: 482: 480: 479: 463: 461: 460: 455: 440: 438: 437: 432: 426: 421: 416: 415: 414: 396: 395: 372: 370: 369: 364: 362: 361: 345: 343: 342: 337: 335: 334: 318: 316: 315: 310: 308: 307: 291: 289: 288: 283: 271: 269: 268: 263: 261: 260: 240: 238: 237: 232: 217: 215: 214: 209: 206: 201: 196: 195: 194: 176: 175: 152: 150: 149: 144: 142: 141: 125: 123: 122: 117: 105: 103: 102: 97: 89: 88: 76: 75: 1137: 1136: 1132: 1131: 1130: 1128: 1127: 1126: 1107: 1106: 1079: 1078: 1069: 1065: 1060: 1024: 1019: 1018: 999: 998: 977: 972: 971: 950: 945: 944: 925: 924: 921: 897: 896: 873: 872: 851: 846: 845: 824: 819: 818: 799: 798: 779: 778: 732: 713: 712: 704: 703: 664: 645: 644: 636: 635: 611: 606: 605: 598: 574: 573: 552: 547: 546: 525: 520: 519: 498: 493: 492: 471: 466: 465: 446: 445: 406: 387: 386: 378: 377: 373:is of the form 353: 348: 347: 326: 321: 320: 299: 294: 293: 274: 273: 252: 247: 246: 223: 222: 186: 167: 166: 158: 157: 133: 128: 127: 108: 107: 80: 67: 62: 61: 58: 24:(also known as 22:Craig's theorem 12: 11: 5: 1135: 1133: 1125: 1124: 1119: 1109: 1108: 1105: 1104: 1092: 1077: 1076: 1062: 1061: 1059: 1056: 1046:Carl G. Hempel 1031: 1027: 1006: 984: 980: 957: 953: 932: 920: 917: 904: 880: 858: 854: 831: 827: 806: 786: 775: 774: 760: 757: 754: 751: 745: 739: 735: 731: 728: 725: 720: 716: 697: 696: 683: 677: 671: 667: 663: 660: 657: 652: 648: 618: 614: 597: 594: 581: 559: 555: 532: 528: 505: 501: 478: 474: 453: 442: 441: 430: 425: 419: 413: 409: 405: 402: 399: 394: 390: 360: 356: 333: 329: 306: 302: 281: 259: 255: 230: 219: 218: 205: 199: 193: 189: 185: 182: 179: 174: 170: 153:consisting of 140: 136: 115: 95: 92: 87: 83: 79: 74: 70: 57: 54: 13: 10: 9: 6: 4: 3: 2: 1134: 1123: 1120: 1118: 1115: 1114: 1112: 1102: 1101: 1096: 1095:Hilary Putnam 1093: 1090: 1089: 1084: 1083:William Craig 1081: 1080: 1073: 1067: 1064: 1057: 1055: 1052: 1051:Hilary Putnam 1047: 1029: 1025: 1004: 982: 978: 955: 951: 930: 918: 916: 902: 894: 878: 856: 852: 829: 825: 804: 784: 755: 749: 743: 737: 733: 729: 726: 723: 718: 714: 702: 701: 700: 681: 675: 669: 665: 661: 658: 655: 650: 646: 634: 633: 632: 616: 612: 603: 595: 593: 579: 557: 553: 530: 526: 503: 499: 476: 472: 451: 428: 423: 417: 411: 407: 403: 400: 397: 392: 388: 376: 375: 374: 358: 354: 331: 327: 304: 300: 279: 257: 253: 244: 228: 203: 197: 191: 187: 183: 180: 177: 172: 168: 156: 155: 154: 138: 134: 113: 93: 90: 85: 81: 77: 72: 68: 55: 53: 51: 50:William Craig 47: 43: 42:axiomatizable 39: 35: 31: 27: 26:Craig's trick 23: 19: 1098: 1086: 1070:A. Visser, " 1066: 922: 776: 698: 599: 443: 220: 59: 25: 21: 15: 1111:Categories 1058:References 744:⏟ 730:∧ 727:⋯ 724:∧ 676:⏟ 662:∧ 659:⋯ 656:∧ 531:∗ 477:∗ 418:⏟ 404:∧ 401:⋯ 398:∧ 359:∗ 332:∗ 305:∗ 258:∗ 198:⏟ 184:∧ 181:⋯ 178:∧ 139:∗ 94:… 777:where 631:with 241:. The 36:of a 970:and 871:and 272:and 60:Let 923:If 773:(*) 245:of 32:of 16:In 1113:: 52:. 20:, 1030:A 1026:V 1005:T 983:B 979:V 956:A 952:V 931:T 903:j 879:j 857:i 853:A 830:i 826:A 805:i 785:f 759:) 756:i 753:( 750:f 738:i 734:A 719:i 715:A 682:i 670:i 666:A 651:i 647:A 617:i 613:A 580:T 558:n 554:A 527:T 504:j 500:A 473:T 452:j 429:. 424:j 412:j 408:B 393:j 389:B 355:T 328:T 301:T 280:T 254:T 229:i 204:i 192:i 188:A 173:i 169:A 135:T 114:T 91:, 86:2 82:A 78:, 73:1 69:A

Index

mathematical logic
recursively enumerable set
well-formed formulas
first-order language
axiomatizable
Craig interpolation
William Craig
deductive closures
primitive recursive
Kleene's T predicate
Carl G. Hempel
Hilary Putnam
Vaught's Theorem on Axiomatizability by a Scheme
William Craig
The Journal of Symbolic Logic
Hilary Putnam
The Journal of Philosophy
Categories
Computability theory
Theorems in the foundations of mathematics

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