Dear Members of the Research Community, A frequent and ongoing impediment in mathematical research is an only partial understanding of the nature of antinomies, in which _self-reference_ is (correctly) identified as a characteristic of the antinomy, but in which it is also omitted that - as is well known in philosophy - _negation_ is the second necessary characteristic of an antinomy.
For example, in his article "The Foundation of a Generic Theorem Prover" (1988) introducing Isabelle's meta-logic, Larry Paulson writes: "A logic for the formalization of mathematics must presuppose the very minimum. Philosophers have debated whether a logic must be _predicative_ - free of 'vicious circles'" [Paulson, 1988, p. 33, emphasis as in the original]. http://www.cl.cam.ac.uk/techreports/UCAM-CL-TR-130.pdf Or, for example, when I met Peter (Peter Andrews, the creator of the mathematical higher-order logic Q0) in 2010 and mentioned that in my logic R0 there is a universal type (omega) containing all mathematical objects, including itself, he made a joke: "That's when logicians get nervous!" Obviously, the origin of this view is Bertrand Russell's article "Mathematical Logic as based on the Theory of Types" (1908), in which type theory was introduced in order to avoid the inconsistency arising from Russell's paradox (found independently by Russell and Zermelo) that Russell discovered in 1901, communicated in a letter to Frege in 1902, and first published in "The Principles of Mathematics" in 1903: I. "In all the above contradictions (which are merely selections from an indefinite number) there is a common characteristic, which we may describe as self-reference or reflexiveness." [Russell, 1908, p. 224; see also Russell, 1967b, p. 154] II. "IV. / _The Hierarchy of Types_. / [...] The division of objects into types is necessitated by the reflexive fallacies which otherwise arise. These fallacies, as we saw, are to be avoided by what may be called the 'vicious-circle principle;' i.e., 'no totality can contain members defined in terms of itself.'" [Russell, 1908, pp. 236 f., emphasis as in the original; see also Russell, 1967b, p. 163] However, the classical antinomy has two characteristics, or, actually, three: 1. self-reference, 2. negation, 3. and the negation has to be applied to the self-reference (and not to something else). It can easily be observed that all three characteristics hold for Russell's paradox: The set of all sets that do NOT contain THEMSELVES. In order to make this philosophical insight plausible for mathematicians, I have compiled three quotes from (some of) the most important philosophical works on this topic (citations in German as written in the original works, followed by my own translations): 1. "Strikte Antinomien sind von bloßen Widersprüchen unterschieden. Eine strikte Antinomie weist immer zwei sich gegenseitig negierende und zugleich wechselseitig implizierende Seiten auf, während bei einem einfachen Widerspruch bloß eine Konjunktion kontradiktorisch entgegengesetzter Bestimmungen bzw. Aussagen vorliegt. [...] / Zwei Aspekte sind für Antinomien konstitutiv, das _Me[r]kmal der Selbstbeziehung_ und das _Merkmal der Negation_, wobei der interne Zusammenhang dieser beiden Merkmale so aussieht, daß dasjenige, was negiert wird, nicht irgend eine beliebige Eigenschaft ist, sondern die Selbstbeziehung. Die Negation, die Negation von Selbstbeziehung ist, ist aber genau das, was bei Hegel sich auf sich beziehende Negation heißt. Die Negation von Selbstbeziehung ist darin antinomisch, daß sie sich als ein Modus von Selbstbeziehung erweist: Die Negation ist als Negation der Selbstbeziehung selbstbezügliche Negation." [Iber, 1990, S. 482, Hervorhebungen im Original] "Strict antinomies are distinct from mere contradictions. A strict antinomy always has two sides that simultaneously negate and reciprocally imply each other, whereas, in a simple contradiction, there is just a conjunction of two contradictorily opposing properties or propositions. [...] / Two aspects are constitutive for antinomies, the _property of self-reference_ and the _property of negation_, whereas the internal relationship of these two properties is such that what is negated is not some arbitrary property, but the self-reference. However, the negation, which is the negation of self-reference, is exactly what Hegel calls the self-referencing negation. The negation of self-reference is antinomical insofar, as it proves to be a mode of self-reference: The negation as a negation of self-reference is a self-referencing negation." [Iber, 1990, p. 482, emphases as in the original; translation by the author] 2. "[...] Negation und Selbstbeziehung [sind] 'die beiden Charakteristika strikter Antinomien', wobei das Negierte die Selbstbeziehung selbst sein muss und nicht irgendeine Eigenschaft (wie bei dem Begriff 'nicht farbig', der eben [selbst] nicht farbig ist)." [S. Schick, 2010, S. 343] "[...] Negation and self-reference [are] 'the two characteristics of strict antinomies', while that which is negated has to be the self-reference itself and not an arbitrary property (as with the notion 'not colored', which [itself] is not colored)." [S. Schick, 2010, p. 343; translation by the author] 3. "Die Reflexionslogik behandelt entsprechend die Kategorien der Identität und des Unterschieds, der Verschiedenheit, des Gegensatzes und schließlich des Widerspruchs. [...] Die Beziehungen, die die Reflexion als formallogisches Denken _setzt_, sind zunächst solche abstrakter Identität bzw. ebenso abstrakter Unterscheidung. Die Reflexion auf die Kategorien von Identität und Unterschied zeigt indessen, dass diese für sich isoliert gar nicht bestimmbar sind, d.h. ihr Anderes _logisch_ in sich enthalten: '... der Unterschied an sich ist der sich auf sich beziehende Unterschied; so ist er die Negativität seiner selbst, der Unterschied nicht von einem Andern, sondern seiner von sich selbst. [...] - Dies ist als die _wesentliche Natur der Reflexion_ und als _bestimmter Urgrund aller Tätigkeit und Selbstbewegung_ zu betrachten. - [...]'" [Wagenknecht, 2013b, S. 74 f., Hervorhebungen im Original, ursprünglich 1997 veröffentlicht] (Das Zitat im Zitat stammt aus dem zweiten Kapitel der Wesenslogik in Hegels _Wissenschaft der Logik_ [Hegel, 1986 ff., Bd. 6, S. 46 f., ursprünglich 1813 veröffentlicht]. Diesen Teil, die Reflexionslogik, bezeichnet Hegel selbst als "(de[n] schwerste[n]) Teil" [Hegel, 1986 ff., Bd. 8, S. 236 (Enz. § 114), ursprünglich 1817 veröffentlicht, zitiert nach der letzten (dritten) Ausgabe seiner _Enzyklopädie_ von 1830] seines Hauptwerks _Wissenschaft der Logik_, des mit Abstand wichtigsten Werks Hegels überhaupt.) "Accordingly, the logic of reflection treats the categories of identity and of difference, of diversity, of opposition, and, finally, of the contradiction. [...] The relations _set_ by the reflection as formal logic are, first of all, those of abstract identity or those of likewise abstract distinction. The reflection on the categories of identity and difference indeed shows that those cannot be determined in an isolated manner, i.e., _logically_ contain their other: '... the difference in itself is self-related difference; as such, it is the negativity of itself, the difference not of an other, but of itself from itself. [...] - This is to be considered as the _essential nature of reflection_ and as the _specific, original ground of all activity and self-movement_. - [...]'" [Wagenknecht, 2013b, pp. 74 f., emphases as in the original, originally published in 1997; translation by the author] (The quote within the quote is taken from the second chapter of the logic of essence in Hegel's _Science of Logic_ [Hegel, 1986 ff., vol. 6, pp. 46 f., originally published in 1813; translation by the author]. Hegel himself calls this part, the logic of reflection, "(the most difficult) part" [Hegel, 1986 ff., vol. 8, p. 236 (Enc. § 114), originally published in 1817, quoted from the last (third) edition of his _Encyclopedia_ from 1830; translation by the author] of his main work _Science of Logic_, which is by far Hegel's most important work.) Finally, it should be noted that the antinomy is distinct from the mere contradiction in formal logic and mathematics, as from the strict antinomy, a contradiction is obtained without premises (without non-logical axioms, assumptions, or hypotheses), i.e., from the logic (the formal language, the logistic system) only, as in the case of Russell's paradox: 4. "Tatsächlich aber ist das, was Kant als Antinomie bezeichnet, weder eine echte Antinomie noch eine Antinomie im Sinne Hegels. Wenn Antinomien logische Widersprüche sind, 'die _prämissenfrei_ abgeleitet werden', dann liegen bei Kant keine eigentlichen Antinomien vor, denn die entgegengesetzten Behauptungen implizieren einander nicht, sondern beruhen auf verschiedenen Voraussetzungen." [S. Schick, 2010, S. 339 f., Hervorhebung im Original] "But, indeed, that which Kant calls an antinomy is neither a true antinomy nor an antinomy as understood by Hegel. If antinomies are logical contradictions, 'which are derived _without premises_', then in Kant's case there are no actual antinomies, since the opposing propositions do not imply each other, but depend on different assumptions." [S. Schick, 2010, pp. 339 f., emphasis as in the original; translation by the author] Using this terminology, it becomes clear that the chapters "The Contradiction" ("Der Widerspruch") both in book two of Hegel's _Science of Logic_, _The Doctrine of Essence_ (1813), [Hegel, 1986 ff., vol. 6, pp. 64 ff.] and in Russell's "The Principles of Mathematics" (1903) [Russell, 1903, pp. 101 ff.] should actually be entitled "The Antinomy" ("Die Antinomie"). http://www.deutschestextarchiv.de/book/view/hegel_logik0102_1813?p=77 https://archive.org/stream/principlesmathe00russgoog#page/n132/mode/1up In this chapter in _The Doctrine of Essence_ (_Die Lehre vom Wesen_), commonly called the logic of essence (Wesenslogik), Hegel wrote: 5. "Dies ist also derselbe Widerspruch [...], nämlich [...] Negation, als Beziehung auf sich." [Hegel, 1986 ff., Bd. 6, S. 66, ursprünglich 1813 veröffentlicht] "This is therefore the same contradiction [...], namely [...] negation as self-reference." [Hegel, 1986 ff., vol. 6, p. 66, originally published in 1813; translation by the author] http://www.deutschestextarchiv.de/book/view/hegel_logik0102_1813?p=79 For philosophical references, please see: http://doi.org/10.4444/100.110 For mathematical references, please see: http://doi.org/10.4444/100.111 Kind regards, Ken Kubota ____________________________________________________ Ken Kubota http://doi.org/10.4444/100 ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ hol-info mailing list hol-info@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/hol-info