•  175
    The Tree Theory and Isomorphism
    Analysis 41 (1): 6-11. 1980.
    A main thesis of Fred Sommers' type theory, is that an isomorphism exists between any natural language and the categories discriminated by that language. Here the author gives an explanation of what this claim comes to. And then it is argued that, so understood, the claim is incompatible with Zermelo-Fraenkel set theory. Finally, it is argued against trying to salvage the isomorphism thesis by appealing to some other set theory.
  •  130
    The Lessons of the Liar
    Theory and Decision 11 (1): 55-70. 1979.
    The paper argues that the liar paradox teaches us these lessons about English. First, the paradox-yielding sentence is a sentence of English that is neither true nor false in English. Second, there is no English name for any such thing as a set of all and only true sentences of English. Third, ‘is true in English’ does not satisfy the axiom of comprehension.
  •  53
    Two philosophical theories, mathematical Platonism and nominalism, are the background of six dialogues in this book. There are five characters in these dialogues: three are nominalists; the fourth is a Platonist; the main character is somewhat skeptical on most issues in the philosophy of mathematics, and is particularly skeptical regarding the two background theories.
  •  499
    Mark Steiner criticizes some remarks Wittgenstein makes about Gödel. Steiner takes Wittgenstein to be disputing a mathematical result. The paper argues that Wittgenstein does no such thing. The contrast between the realist and the demonstrativist concerning mathematical truth is examined. Wittgenstein is held to side with neither camp. Rather, his point is that a realist argument is inconclusive
  •  317
    Tarski and Proper Classes
    Analysis 40 (4): 6-11. 1980.
    In this paper the authors argue that if Tarski’s definition of truth for the calculus of classes is correct, then set theories which assert the existence of proper classes (classes which are not the member of anything) are incorrect.
  • Chapter 2: Notes to Grundlagen
    Poznan Studies in the Philosophy of the Sciences and the Humanities 90 45-72. 2006.
  •  1353
    Quine and his Critics on Truth-Functionality and Extensionality
    Logic and Logical Philosophy 16 (1): 45-63. 2007.
    Quine argues that if sentences that are set theoretically equivalent are interchangeable salva veritate, then all transparent operators are truth-functional. Criticisms of this argument fail to take into account the conditional character of the conclusion. Quine also argues that, for any person P with minimal logical acuity, if ‘belief’ has a sense in which it is a transparent operator, then, in that sense of the word, P believes everything if P believes anything. The suggestion is made that he …Read more
  •  266
    Prior’s Theory of Propositions
    Analysis 37 (3): 104-112. 1977.
    Prior propounded a theory that, if correct, explains how it is possible for a statement about propositions to be true even if there are no propositions. The major feature of his theory is his treatment of sentence letters as bindable variables in non-referential positions. His theory, however, does not include a semantical account of the resulting quantification. The paper tries to fill that gap.
  •  125
    Assertion and belief
    Philosophical Studies 17 (5). 1966.
    This paper is written in opposition of various antecedent discussions of Moore’s paradox. It concludes that one cannot make an honest and primary truth-claim by producing ‘p, but I believe not-p’.
  •  243
    A problem about conversational implicature
    Linguistics and Philosophy 3 (1). 1979.
    Conversational implicatures are easy to grasp for the most part. But it is another matter to give a rational reconstruction of how they are grasped. We argue that Grice's attempt to do this fails. We distinguish two sorts of cases: (1) those in which we grasp the implicature by asking ourselves what would the speaker have to believe given that what he said is such as is required by the talk exchange; (2) those in which we grasp the implicature by asking ourselves why it is that what the speaker …Read more
  •  286
    More on propositional identity
    Analysis 39 (3): 129-132. 1979.
    We give a semantical account of propositional identity which is stronger than mutual entailment. That is, according to our account: (1) if A = B is true in a model, so are A 'validates' B and B 'validates' A. (2) There exist models m such that A 'validates' B and B 'validates' A are true in m but A = B is not true in m. According to our account the following rule is sound: (3) from (.. A..) = (.. B..) infer A = B. The paper is a response to a paper by James Freeman to an earlier paper by us.
  •  664
    Offices and God
    Sophia 29 (3): 29-34. 1990.
    Pavel Tichy presents an interpretation of Anselm’s Proslogion III argument. Tichy presents an interpretation of this argument and raises doubts about one of the premises. The authors contend that Tichy’s interpretation of Anselm is wrong. The argument Tichy comes to raise doubts about is not Anselm’s.
  •  173
    Do we need quantification?
    Notre Dame Journal of Formal Logic 25 (4): 289-302. 1984.
    The standard response is illustrated by E, J. Lemmon's claim that if all objects in a given universe had names and there were only finitely many of them, then we could always replace a universal proposition about that universe by a complex proposition. It is because these two requirements are not always met that we need universal quantification. This paper is partly in agreement with Lemmon and partly in disagreement. From the point of view of syntax and semantics we can replace a universal prop…Read more
  •  150
    System relativism
    Ratio 1 (2): 163-175. 1988.
    The fundamental thought of moral relativism is set out as follows: moral criteria, derived from overall moral points of view, are used to derive particular moral judgments. Thus such a judgment might be correct relative to one overall moral point of view and incorrect relative to another. The evaluation of an overall moral point of view does not involve the application of moral criteria. Rather, the evaluation of a morality takes us outside the province of morality. The result of sharpening this…Read more
  • Editor's Introduction
    Poznan Studies in the Philosophy of the Sciences and the Humanities 90 11-21. 2006.
  •  240
    What is a second order theory committed to?
    Erkenntnis 20 (1). 1983.
    The paper argues that no second order theory is ontologically commited to anything beyond what its individual variables range over.
  •  1140
    Fundamental to Quine’s philosophy of logic is the thesis that substitutional quantification does not express existence. This paper considers the content of this claim and the reasons for thinking it is true.
  •  90
    A Conversation about Numbers and Knowledge
    American Philosophical Quarterly 39 (3): 275-287. 2002.
    This is a dialogue in the philosophy of mathematics. The dialogue descends from the confident assertion that there are infinitely many numbers to an unresolved bewilderment about how we can know there are any numbers at all. At every turn the dialogue brings us only to realize more fully how little is clear to us in our thinking about mathematics.
  •  127
    Four views of arithmetical truth
    Philosophical Quarterly 40 (159): 155-168. 1990.
    Four views of arithmetical truth are distinguished: the classical view, the provability view, the extended provability view, the criterial view. The main problem with the first is the ontology it requires one to accept. Two anti-realist views are the two provability views. The first of these is judged to be preferable. However, it requires a non-trivial account of the provability of axioms. The criterial view is gotten from remarks Wittgenstein makes in Tractatus 6.2-6.22 . It is judged to be th…Read more
  • Chapter 4: The Peano Axioms
    Poznan Studies in the Philosophy of the Sciences and the Humanities 90 105-128. 2006.
  •  306
    True Propositions: A Reply to C.J.F. Williams
    Analysis 32 (3): 101-106. 1972.
    This paper replies to points Williams makes to his reply to Sayward’s criticism of Williams’s proposal of ‘for some p ___ states that p & p’ as an analysis of ‘___ is true’.
  •  1167
    The Internal/External Question
    Grazier Philosophishe Studien 47 31-41. 1994.
    For Rudolf Carnap the question ‘Do numbers exist?’ does not have just one sense. Asked from within mathematics, it has a trivial answer that could not possibly divide philosophers of mathematics. Asked from outside of mathematics, it lacks meaning. This paper discusses Carnap ’s distinction and defends much of what he has to say
  •  11
    Book Reviews (review)
    Mind 100 (397): 137-139. 1991.
  •  182
    Relativism and ontology
    Philosophical Quarterly 37 (148): 278-290. 1987.
    This paper deals with the question of whether there is objectivist truth about set-theoretic matters. The dogmatist and skeptic agree that there is such truth. They disagree about whether this truth is knowable. In contrast, the relativist says there is no objective truth to be known. Two versions of relativism are distinguished in the paper. One of these versions is defended.
  •  160
    A conversation about numbers
    Philosophia 29 (1-4): 191-209. 2002.
    This is a dialogue in which five characters are involved. Various issues in the philosophy of mathematics are discussed. Among those issues are these: numbers as abstract objects, our knowledge of numbers as abstract objects, a proof as showing a mathematical statement to be true as opposed to the statement being true in virtue of having a proof.
  • Chapter 7: Arithmetic and Rules
    Poznan Studies in the Philosophy of the Sciences and the Humanities 90 183-211. 2006.
  •  186
    On some much maligned remarks of Wittgenstein on gödel
    Philosophical Investigations 24 (3). 2001.
    In "Remarks on the Foundations of Mathematics" Wittgenstein discusses an argument that goes from Gödel’s incompleteness result to the conclusion that some truths of mathematics are unprovable. Wittgenstein takes issue with this argument. Wittgenstein’s remarks in this connection have received very negative reaction from some very prominent people, for example, Gödel and Dummett. The paper is a defense of what Wittgenstein has to say about the argument in question.
  •  41
    Prior and Lorenzen on Quantification
    Grazer Philosophische Studien 41 (1): 151-173. 1991.