‎Ueber die Endlichkeit des Invariantensystems für binäre grundformen (+) Ueber Büschel von binären Formen mit vorgeschriebener Functionaldeterminante. - [""WITHOUT DOUBT THIS IS THE MOST IMPORTANT WORK ON GENERAL ALGEBRA""]‎

‎Leipzig, B.G. Teubner, 1888. 8vo. Original printed wrappers, no backstrip and a small nick to front wrapper. In ""Mathematische Annalen. Begründet 1888 durch Rudolf Friedrich Alfred Clebsch. XXXIII.[33] Band. 2. Heft."" Entire issue offered. Internally very fine and clean. [Hilbert:] Pp. 223-6"" Pp.227-36 [Entire issue: Pp. 161-316].‎

‎First printing of Hilbert's exceedingly important and groundbreaking paper in which he proved his famous Basis Theorem that is, if every ideal in a ring R has a finite basis, so does every ideal in the polynomial ring R[x]. Hilbert had thus connected the theory of invariants to the fields of algebraic functions and algebraic varieties. When Felix Klein read the paper he wrote ""I do not doubt that this is the most important work on general algebra that the Mathematische Annalen has ever published.""Hilbert submitted a paper proving the finite basis theorem to Mathematische Annalen. However Gordan was the expert on invariant theory for the journal and he found Hilbert's revolutionary approach difficult to appreciate. He refereed the paper and sent his comments to Klein:""The problem lies not with the form ... but rather much deeper. Hilbert has scorned to present his thoughts following formal rules, he thinks it suffices that no one contradict his proof ... he is content to think that the importance and correctness of his propositions suffice. ... for a comprehensive work for the Annalen this is insufficient.""Gordan rejected the article. His - now famous - comment was: Das ist nicht Mathematik. Das ist Theologie. (i.e. This is not Mathematics. This is Theology).However, Hilbert had learnt through his friend Hurwitz about Gordan's letter to Klein and Hilbert wrote himself to Klein in forceful terms:""... I am not prepared to alter or delete anything, and regarding this paper, I say with all modesty, that this is my last word so long as no definite and irrefutable objection against my reasoning is raised.""At the time Klein received these two letters from Hilbert and Gordan, Hilbert was an assistant lecturer while Gordan was the recognised leading world expert on invariant theory and also a close friend of Klein's. However Klein recognised the importance of Hilbert's work and assured him that it would appear in the Annalen without any changes whatsoever, as indeed it did. Hilbert expanded on his methods in a later paper, again submitted to the Mathematische Annalen [1893] and Klein,after reading the manuscript, wrote to Hilbert saying:-I do not doubt that this is the most important work on general algebra that the Annalen has ever published.Later, after the usefulness of Hilbert's method was universally recognized, Gordan himself said: ""I have convinced myself that even theology has its merits"".(Klein. Development of mathematics in the 19th century. P. 311).Sometimes Hilbert's first publication of the Basis Theorem is referred to as being published in the paper ""Zur Theorie der algebraischen Gebilde"" in Göottinger Nachrichten in 1888. This, however, was published in December 1888 and the present issue was published in March. ‎

‎Ueber die gerade Linie als kürzeste Verbindung zweier Punkte. (Aus einem an Herrn F. Klein gerichteten Briefe). - [FIRST PUBLICATION OF THE HILBERT METRIC]‎

‎Leipzig, B.G. Teubner, 1895. 8vo. Original printed wrappers, no backstrip. In ""Mathematische Annalen. Begründet durch Alfred Clebsch und Carl Neumann. 46. Band. 1. Heft.""Entire issue offered. Internally very fine and clean. [Hilbert:] Pp. 91-96. [Entire issue: IV, 160 pp].‎

‎First printing of Hilbert's groundbreaking paper in which ""Hilbert's Metric"" (or Hilbert's projective metric) - and the metric in general - was introduced. The Hilbert metric an a closed convex cone that can be applied to various purposed in non-Euclidean geometryThe usefulness of Hilbert's metric were made clear in 1957 by Garrett Birkhoff who showed that the Perron-Frobenius theorem for non-negative matrices and Jentzch's theorem for integral operators with positive kernel could both be proved by an application of the Banach contraction mapping theorem in suitable metric spaces. (Serrin. Hilbert's Matric. P. 1). ‎

‎Ueber die reellen Züge algebraischer Curven.‎

‎Leipzig, B.G. Teubner, 1891. 8vo. Original printed wrappers, no backstrip. In ""Mathematische Annalen. Begründet durch Alfred Clebsch und Carl Neumann. 38. Band. 1. Heft."".(Entire issue offered). Titlepage to Bd. 38. IV,160 pp. a. 1 folded plate. Hilbert's paper: pp. 115-138.‎

‎First apperance of an importent paper on algebraic geometry.The issue contains also Felix Klein ""Ueber Normierung der linearen Differentialgleichungen zweiter Ordnung"", pp. 144-152.‎

‎Ueber die Theorie des relativquadratischen Zahlkörpers. - [A MAIN WORK ON ALGEBRAIC NUMBER-THEORY]‎

‎Leipzig, B.G. Teubner, 1898. Orig. printed wrappers, no backstrip. In: ""Mathematische Annalen begründet durch Alfred Clebsch und Carl Neumann."", 51. Bd., 1. Heft. The whole issue offered (=Heft 1). IV,160 pp. Hilbert's paper pp. 1-127.‎

‎First edition of Hilbert's famous report on algebraic numbers.""The work on algebraic number theory was climaxed in the nineteenth century by Hilbert's famous report on algebraic numbers. This report is primarely an account of what had been done during the century. However Hilbert reworked all of this earlier theory and gave a new, elegant and powerfull methods of securing these results. He had begun to create new ideas in algebraic number theory from about 1892 on and one of the new creations on Galoisian number fields was also incorporated in the report."" (Morris Kline in ""Mathematical Thoughts..."" pp. 825).‎

‎Ueber die Vollen Invariantensysteme.‎

‎Leipzig, B.G. Teubner, 1893. 8vo. Original printed wrappers, no backstrip. In ""Mathematische Annalen. Begründet 1893 durch Alfred Clebsch und Carl Neumann. 42. Band. 3. Heft."" Entire issue offered. [Hilbert:] Pp. 314-73. [Entire issue: Pp. 314-604].‎

‎First printing of Hilbert's fundamental landmark paper in which he ""INTRODUCED STUNNING NEW IDEAS WHICH HAVE DEEPLY INFLUENCED THE DEVELOPMENT OF MODERN ALGEBRA AND ALGEBRAIC GEOMETRY."" (Buchberger. Gröbner bases and applications. P. 63). The ideas presented in the present paper was introduced in his 1890-paper, but here he ""called attention to the fact that his earlier results failed to give any idea of how a finite basis for a system of invariants could actually be construted. [...] To show how these drawbacks could be overcome, Hilbert thus adopted an even more general standpoint [...]. He described the guiding idea of this culminating paper of 1893 as invariants could actually be constructed"". (Hendricks. Proof theory: history and philosophical significance. P. 59) Hilbert's first work on invariant functions led him to the demonstration in 1888 of his famous finiteness theorem. Twenty years earlier, Paul Gordan had demonstrated the theorem of the finiteness of generators for binary forms using a complex computational approach. Attempts to generalize his method to functions with more than two variables failed because of the exceedingly complicated calculations involved. Hilbert realized that it was necessary to take a completely different path. Hilbert sent his results to the Mathematische Annalen. Gordan, the expert on the theory of invariants for the Mathematische Annalen, did not appreciate the revolutionary nature of Hilbert's theorem and rejected the article. His - now famous - comment was: Das ist nicht Mathematik. Das ist Theologie. (i.e. This is not Mathematics. This is Theology).Klein, on the other hand, recognized the importance of the work immediately, and guaranteed that it would be published without the slightest alterations. Encouraged by Klein and by the comments of Gordan, Hilbert extended his method in a second article, providing estimations on the maximum degree of the minimum set of generators, and he sent it once more to the Annalen. After having read the manuscript, Klein wrote to him, saying: ""WITHOUT DOUBT THIS IS THE MOST IMPORTANT WORK ON GENERAL ALGEBRA that the Annalen has ever published.""Later, after the usefulness of Hilbert's method was universally recognized, Gordan himself said: ""I have convinced myself that even theology has its merits"".(Klein. Development of mathematics in the 19th century. P. 311).‎

‎Ueber einen allgemeinen Gesichtspunkt für invariantentheorietische Untersuchungen im binären Formengebiete.‎

‎Leipzig, B.G. Teubner, 1887. 8vo. Bound in recent full black cloth with gilt lettering to spine. In ""Mathematische Annalen"", Volume 28., 1887. Entire volume offered. Library label pasted on to pasted down front free end-paper. Small library stamp to lower part of verso of title page. Very fine and clean. Pp. 381-446. [Entire volume: Pp. IV, 600.]‎

‎First printing of Hilbert's ""Habilitationsschrift"", a fundamental work on algebraic invariants. With this he meant to revolutionize the feld by several new methods thatplay no part in the 1888 proof but would reappear to some extent in Hilbert’s (1891-92" 1893) response to Gordan’s criticism. By that time Hilbert’s resultsplus further ones by Gordan would solve Gordan’s problem.‎

‎Zur Variationsrechnung. - [HILBERT'S 23RD PROBLEM]‎

‎Leipzig, B. G. Teubner, 1906. 8vo. In the original printed wrappers, without backstrip. In ""Mathematische Annalen, 62. Band., 3. Heft., 1906."". A fine and clean copy. Pp. 351-370. [Entire issue: Pp. 329-448.].‎

‎First printing of Hibert's important paper in which he addressed a number of topics in the Calculus of Variations and thereby extended the ideas given in his account of the 23rd problem. In contrast with Hilbert's other 22 problems, his 23rd is not so much a specific ""problem"" as an encouragement towards further development of the calculus of variations. His work in the present paper led to a modern definition of the field.‎

‎Über den Begriff der Klasse von Differentialgleichungen.‎

‎Leipzig, B.G. Teubner, 1912. 8vo. Bound in half cloth with the original wrappers. Marbled boards. In ""Mathematische Annalen. Herausgegeben von A. Clebsch und C. Neumann. 73. Band, Heft 1-4, 1912"". Black leather title label to spine with gilt lettering. Library label pasted on to top of spine and library stamp to title page. Light writing in pencil to front wrapper. [Hilbert:] Pp. 95-108. [Entire issue: IV, (2), 599, (1)].‎

‎First printing of Hilbert's paper on on the concept of the class of differential equations.The issue contain many other papers by contemporary mathematicians.‎

‎Über die Transcendenz der Zahlen e und pi. - [ANTICIPATION OF HILBERT'S SEVENTH PROBLEM]‎

‎Leipzig, B.G. Teubner, 1893. 8vo. Original printed wrappers, no backstrip and a small nick to front wrapper. In ""Mathematische Annalen. Begründet 1868 durch Rudolf Friedrich Alfred Clebsch. 43. Band. 2. und 3. (Doppel-)Heft.""Entire issue offered. Internally very fine and clean. [Hilbert:] Pp. 216-19. [Entire issue: Pp. 145-456].‎

‎First publication of Hilbert's important contribution to transcendental number theory which anticipates Hilbert's seventh problem, the seventh of twenty-three problems proposed by Hilbert in 1900 which became of seminal importance to 20th century mathematics. A transcendental number is a number which is not algebraic-that is, it is not a root of a non-constant polynomial equation with rational coefficients. The most prominent examples of transcendental numbers are pi and e. Euler was the first person to define transcendental numbers - The name ""transcendentals"" comes from Leibniz in his 1682 paper where he proved sin x is not an algebraic function of x.‎

‎Über eine Darstellungsweise der invarianten Gebilde in binären Formengebiete (+) Ueber die Singularitäten der Discriminantenfläche (+) Ueber binäre Formenbüschel mit besonderen Combinanteneigenschaften.‎

‎Leipzig, B. G. Teubner, 1887. 8vo. Bound in recent full black cloth with gilt lettering to spine. In ""Mathematische Annalen"", Volume 30, 1887. Entire volume offered. Library label pasted on to pasted down front free end-paper. Small library stamp to lower part of title title page and verso of title page. Very fine and clean. Pp. 15-29" 437-441" Pp. 561-570. [Entire volume: IV, 596 pp.].‎

‎First printing of these early three papers by Hilbert. David Hilbert, one of the most influential mathematicians of the 19th and early 20th centuries, is probably best known for the ""Hilbert Problems"" - a list of twenty-three problems in mathematics all unsolved at the time, and several of them were very exceedingly influential for 20th century mathematics.He is regarded as one of the founders of proof theory and mathematical logic, as well as for being among the first to distinguish between mathematics and metamathematics.""Hermann Weyl described his teacher Hilbert's style: ""It is as if you were on a swift walk through a sunny open landscape" you look freely around, demarcation lines and connecting roads are pointed out to you, before you must brace yourself to climb the hill" then the path goes straight up."" (Princeton Companion to Mathematics). The present volume contain several other papers by influential contemporary mathematicians. ‎

‎Über ternäre definite Formen.‎

‎(Berlin, Stockholm, Paris, 1893). 4to. Without wrappers as extracted from ""Acta Mathematica. Hrsg. von G. Mittag-Leffler."", Vol. 17, pp. 169-197.‎

‎First edition. This importent paper constitutes Hilbert's own version of part of the solution of his ""Mathematische Probleme"" listed at the International mathematical Congress in Paris 1900 (as problem 17) on the ""Expression of definite forms by squares"". ""....But since as I have shown, not every definite form can be compounded by addition from squares of forms, the question arises - which I have answered affirmatively for ternary forms (the paper offered here)- whether every definite form may be expressed as a quotient of sums of squares of forms....""‎

‎Über ternäre definite Formen.‎

‎Stockholm, Beijer, 1893. 4to. As extracted from ""Acta Mathematica, 17. Band]. No backstrip. Fine and clean. Pp. 169-197.‎

‎First edition. This important paper constitutes Hilbert's own version of part of the solution of his ""Mathematische Probleme"" listed at the International mathematical Congress in Paris 1900 (as problem 17) on the ""Expression of definite forms by squares"". ""....But since as I have shown, not every definite form can be compounded by addition from squares of forms, the question arises - which I have answered affirmatively for ternary forms (the paper offered here)- whether every definite form may be expressed as a quotient of sums of squares of forms....""‎

‎Über ternäre definite Formen.‎

‎Stockholm, Beijer, 1893. 4to. Bound in contemporary half cloth with gilt lettering to spine. In ""Acta Mathematica"", Vol, 17, 1883. Entire volume offered. Stamps to title page, otherwise a fine and clean copy. Pp. 169-197. [Entire volume: (6), 416 pp].‎

‎First edition. This important paper constitutes Hilbert's own version of part of the solution of his ""Mathematische Probleme"" listed at the International mathematical Congress in Paris 1900 (as problem 17) on the ""Expression of definite forms by squares"". ""....But since as I have shown, not every definite form can be compounded by addition from squares of forms, the question arises - which I have answered affirmatively for ternary forms (the paper offered here)- whether every definite form may be expressed as a quotient of sums of squares of forms....""‎

‎Ueber einen allgemeinen Gesichtspunkt für invariantentheorietische Untersuchungen im binären Formengebiete.‎

‎Leipzig, B.G. Teubner, 1887. 8vo. Original printed wrappers, no backstrip. In ""Mathematische Annalen. Begründet durch Alfred Clebsch und Carl Neumann. 28. Band. 3. Heft."". (Entire issue offered). Pp. 309-456. Hilbert's paper: pp. 381-446.‎

‎This is Hilbert's ""Habilitationsschrift"", a fundamental work on algebraic invariants.‎

‎Die logischen Grundlagen der Mathematik.‎

‎Berlin, Julius Springer, 1923. 8vo. Full cloth. Spine gone. In: ""Mathematische Annalen begründet durch Alfred Clebsch und Carl Neumann."", 88. Bd. (4),312 pp. (Entire volume offered). Hilbert's paper: pp. 151-165. Internally clean and fine.‎

‎First edition as a continuation of his paper from 1922 ""Neubegründung der Mathematik. Erste Mitteilung"".""This articlee, delivered as a lecture to the deutsche Naturforscher Gesellschaft in Leipzig, September 1922, is a sequel to (neubegründung...), and brings Hilbert's proof theory to maturity. Hilbert here introduces several technical refinements and clarification to his theory. Specifically: (i) he improves the formal system by adding a special sign for formal negation...(ii) he refines his account of the distinction between formal language and the metalanguage....(iii) he outlines a consistency proof for an elementary, quantifier-free formal system of number-theory. (iv) he begins to extend his proof theory to analysis and set theory....sketches a strategy for proving the consistency of a version of Zermel's axiom of choice for real numbers...(etc. etc). (William Ewald in from Kant to Hilbert, vol. II, pp.1134-35).‎

‎Beweis für die Darstellbarkeit der ganzen Zahlen durch eine feste Anzahl nter Potenzen (Waringische Problem).‎

‎Leipzig, B.G. Teubner, 1909. Orig. printed wrappers. No backstrip. In. ""Mathematische Annalen. Hrsg. von Felix Klein, Walther v. Dyck, David Hilbert, Otto Rosenthal"", 67. Bd., 3. Heft. Pp. 281-432 (=3. Heft). Hilbert's paper: pp. 281-300.‎

‎First printing of a groundbreaking work in Number Theory. Edward Waring (1734-98) stated, in his ""Meditationes Algebraicae"" (1770), the theorem known now as ""Waring's Theorem"", that every integer is either a cube or the sum of at most nine cubes"" also every integer is either a fourth power of the sum of at most 19 fourth powers. He conjectured also that every positive integer can be expressed as the sum of at most r kth powers, the r depending on k. These theoremes were not proven by him, but by David Hilbert in the paper offered.Hilbert proves that for every integer n, there exists an integer m such that every integer is the sum of m nth powers. This expands upon the hypotheis of Edward Waring that each positive integer is a sum of 9 cubes (n=3, m=9) and of 19 fourth powers (n= 4, m=19).This issue also contains F. Hausdorff's ""Zur Hilbertschen Lösung des Waringschen Problems"", pp. 301-305.(Se Kline p. 609).‎

‎Über die Theorie der relativ-Abel'schen Zahlkörper [Hilbert] (+) Sur les fonctions abéliennes [Poincaré].‎

‎Berlin, Stockholm, Paris, Beijer, 1902. 4to. Bound in contemporary half cloth with gilt lettering to spine. In ""Acta Mathematica"", Vol. 26, 1802. Entire volume offered. Stamps to title page, otherwise a fine and clean copy. pp. 99-132" Pp. 48-98. [Entire volume: (4), 400 pp.].‎

‎First printing of these two important papers on the theory of quadratic number fields.‎

‎Grundzüge der theoretischen Logik. Dritte, verb. Aufl.‎

‎Berlin, Springer, 1949. Orig. full cloth. A few brownspots to covers. A small stamp on foot of titlepage. VIII,156 pp.‎

‎Grundzüge der theoretischen Logik. Vierte Auflage.‎

‎Berlin, Göttingen..., Springer-Verlag, 1959. Orig. full cloth. VIII,188 pp. A few underlinings and notes.‎

‎Grundzüge der theoretischen Logik. Zweite, verb. Aufl.‎

‎Berlin, Springer, 1938. Orig. printed wrappers. Wr. with tear in spine. VIII,134 pp.‎

‎Grundzüge der Theoretischen Logik. (Die Grundlehren der Mathematischen Wissenshaften in Einzeldarstellungen, Band XXVII).‎

‎Berlin, Julius Springer, 1928. 8vo. Publisher's full cloth. Ink signature of Samuel Skulsky on front free end paper. Completely clean throughout. A fine and tight copy.‎

‎First edition of the foundation of modern mathematical logic.In the years 1917-22 Hilbert gave three seminal courses at the Univeristy og Göttingen on logic and the foundation of mathematics. He received considerable help in preperation and eventual write up of these lectures from Bernays. This material was subsequently reworked by Ackermann into the monograph 'Grundzüge der Theoretischen Logik' (the offered item). It containes the first exposition ever of first-order logic and poses the problem of its completeness and the decision problem ('Entscheidungsproblem'). The first of these questions was answered just a year later by Kurt Gödel in his doctorial dissertation 'Die Vollständigkeit der Axiome des logischen Funktionenkalküls'. This result is known as Gödel's completeness theorem. Two years later Gödel published his famous 1931 paper 'Über formal unentscheidbare Sätze der Principia Mathematica und verwandter Systeme I' in which he showed that a stronger logic, capable of modeling arithmetic, is either incomplete or inconsistent (Gödel's second incompleteness theorem). The later question posed by Hilbert and Ackermann regarding the decision problem was answered in 1936 independantly by Alonzo Church and Allan Turing. Church used his model the lambda-calculus and Turing his machine model to construct undecidable problems and show that the decision problem is unsolvable in first-order logic. These results by Gödel, Church, and Turing rank amongst the most important contributions to mathematical logic ever. Scarce in this condition.‎

‎Advanced Calculus for Applications.‎

‎New Jersey, Prentice-Hall, (1963). Orig. full cloth. IX,646 pp. Name cut from upper corner of titlepage. Clean and fine.‎

‎On the Part of the Motion of Lunar Perigee Which is a Function of the Mean Motions of the Sum and Moon. - [THE HILL DETERMINANT]‎

‎Berlin, Stockholm, Paris, Beijer, 1886. 4to. Bound with the original printed wrappers in contemporary half calf. In ""Acta Mathematica Hrsg. von G. Mittag-Leffler."", Bd. 8. Entires issue offered. Fine and clean. Pp. 1-36 [Entire volume: (4), 392 pp.].‎

‎Second printing (with some additions) of Hill's important paper in he introduced the the Hill Determinant or Hill's Equations""The memoir of 1877 entitled On the Part of the Motion of the Lunar Perigee Which Is a Function of the Mean Motions of the Sun and Moon contains the incontrovertible evidence of Hill’s mathematical genius. He was led to a differential equation, now called Hill’s equation, that is equivalent to an infinite number of algebraic linear equations. Hill showed how to develop the infianite determinant corresponding to these equations.""‎

‎Novi systematis permutationum combinationum ac variationum primae lineae et logisticae serierum formulis analytico-combinatoriis per tabulas exhibendae conspectus et specimina. - [""FOUNDER OF THE COMBINATORIAL SCHOOL IN GERMANY""]‎

‎Leipzig, S. L. Crusium, 1781. 4to. Bound uncut in a nice recent cardboard-binding with red leather title-label to spine with gilt lettering. Title-page partly detached. Occassional brownspotting throughout. XII, LXXXIII, (1) pp.‎

‎Rare first edition of Hindenburg's paper on combinatorics, which partly earned him the title as ""founder of the combinatorial school"" (DSB) in Germany. Combinational mathematics was not new at that time: Pascal, Leibniz, Wallis, the Bernoullis, De Moivre, and Euler, among others, had contributed to it. Hindenburg and his school attempted, through systematic development of combinatorials, to give it a key position within the various mathematical disciplines. ""Combinatorial consideration, especially appropriate symbols, were useful in the calculations of probabilities, in the development of series, in the inversion series, and in the development of formulas for higher differentials. The utility led Hindenburg and his school to entertain great expectations: they wanted combinatorial operations to have the same importance as those of arithmetic, algebra, and analysis. They developed a complicated system of symbols for fundamental combinatorial concepts, such as permutations, variations, and combinations."" (DSB)‎

‎Identity, Variables, and Impredicative Definitions + Vicious Circle Principles and the Paradoxes. (In Journal of Symbolic Logic, Volume 21, Number 3, 1956 + Volume 22, Number 3, 1957). - [HINTIKKA'S TRANSFORMATION RULES]‎

‎(No place), The Association for Symbolic Logic, Inc., 1956 + 1957. 8vo. Both entire issues present, both in original printed wrappers. Volume 21, 3 w. a small loss to lower corner of front wrapper, minor loss to lower capital and a tear to lower front hinge, no loss. Upper corner of least few leaves and back wrappers creased (w. tear to wrapper). Volume 22, 3. w. minor loss to capitals. Both issues internally near mint. Vol. 21, 3: pp. 225-248 (entire issue: pp. 225-336)" Vol. 22, 3: pp. 245-249 (entire issue: pp. 225-336).‎

‎First printing of these two important, but for long overlooked, articles, which together constitute Hintikka's attempt to cope with Wittgenstein's elimination of identity as proposed in the ""Tractatus"". With the translation rules that Hintikka here put forward, he is the first to try to carry out Wittgenstein's suggestions systematically. The Finnish born philosopher and logician, Jaakko Hintikka (born 1929), Professor of Philosophy at the University of Boston, is generally accepted as the founder of formal epistemic logic and of game semantics for logic. He has contributed seminally to the fields of philosophical and mathematical logic, philosophy of mathematics and science, language theory and epistemology. Independently of Evert Willem Beth he discovered the semantic tableau, and he is famous for his work on game semantics and logical quantifiers. In 2005 Hintakka was awarded the Schock Prize in logic and philosophy, the philosophical equivalent to the Nobel prize, ""for his pioneering contributions to the logical analysis of modal concepts, in particular the concepts of knowledge and belief "". In the 1950'ies Hintikka took it upon himself to follow Wittgentein's suggestion of elimination of identity suggested in the ""tractatus"", and in the two offered articles, he succeeds in constructing a logic without identity. The main point of the two connected articles is to show that variables can be used in two ways. One way does not exclude coincidences of the values of different variables (inclusive interpretation of variables), the other does (exclusive interpretation of variables) and can be either weakly or strongly exclusive. He now claims that in the ""Tractatus"" Wittgenstein adopts the weakly exclusive interpretation of variable and then proves that the weakly exclusive quantifiers are able to express everything that the inclusive quantifiers plus identity can express, and without a sign for identity, - for the first time systematically supporting Wittgenstein's claim that identity is not an essential constituent of logical notation. ""There are a number of references to the exclusive interpretations of variables in current logical literature. An exclusive reading of variables was, in effect, suggested by Ludwig Wittgenstein in ""Tractatus logico-philosophicus. As far as I know, however, no one has previously tried to carry out his suggestions systematically. Several misconceptions seem to be current concerning the outcome of an attempts of this kind. Carnap expects radical changes in the rules of substitution. If I am not mistaken, however, at least one form of the exclusive interpretation may be formalized by making but slight alterations in the axioms and/or in the transformation rules of the predicate calculus. Also I hope to say that it is not correct to say (as Russell has done) that Wittgenstein tried to dispense with the notion of identity. What a systematic use of an exclusive reading of variables amounts to is a new way of coping with the notion of identity in a formalized system of logic. Under the most natural formalization of the new interpretations, the resulting system is equivalent to the old predicate calculus (with identity): every formula of the latter admits of a translation into the former, and vice versa."" (Vol. 21, Nr. 3, p. 228).""A deviation from standard English. Recent discussion serves to bring out, amply and convincingly, the utility of observing the ordinary correct use of words and phrases for the purpose of clearing up philosophical problems. In this paper, I shall endeavour to show, by means of an example, that the reverse method may have its interest, too. "" (Vol. 21, Nr. 3, p. 225). ""This note is a sequel to the previous paper of mine which was entitled ""Identity, variables, and impredicative definitions"" and published in this JOURNAL, vol. 21 (1956, pp. 225-245. That early paper served to call attention to the dependency of the set-theoretic paradoxes on the interpretation of the variables that may occur in the critical ""abstraction principle"". (Vol. 22, Nr. 3, p. 245).Besides these two articles, the two issues also include other important articles within logic, e.g. Quine, ""Unification of Universes in Set Theory"" and Symonds and Chisholm ""Inference by Complementary Elimination"".‎