Humankind : a limited company? -- From volume to point: 1. Philosophy, 2. Religion -- Science : specialised but not special -- Cosmic hierarchies -- Consciousness -- Cognition -- In theory -- Back to Genesis -- The beautiful union.
We show that it is not possible to construct a Fraenkel-Mostowski model in which the axiom of choice for well-ordered families of sets and the axiom of choice for sets are both true, but the axiom of choice is false.
Let NBG be von Neumann-Bernays-Gödel set theory without the axiom of choice and let NBGA be the modification which allows atoms. In this paper we consider some of the well-known class or global forms of the wellordering theorem, the axiom of choice, and maximal principles which are known to be equivalent in NBG and show they are not equivalent in NBGA.
The Fraenkel-Mostowski method has been widely used to prove independence results among weak versions of the axiom of choice. In this paper it is shown that certain statements cannot be proved by this method. More specifically it is shown that in all Fraenkel-Mostowski models the following hold: 1. The axiom of choice for sets of finite sets implies the axiom of choice for sets of well-orderable sets. 2. The Boolean prime ideal theorem implies a weakened form of Sikorski's theorem.
The deductive relationships between six statements are examined in set theory without the axiom of choice. Each of these statements follows from the axiom of choice and involves linear orderings in some way.
Introduction: "Know yourself" -- The revelation of God's wisdom -- Credo ut intellegam -- Intellego ut credam -- The relationship between faith and reason -- The interventions of the Magisterium in philosophical matters -- The interaction between philosophy and theology -- Current requirements and tasks -- Conclusion.
The Curry-Howard isomorphism states an amazing correspondence between systems of formal logic as encountered in proof theory and computational calculi as found in type theory. For instance, minimal propositional logic corresponds to simply typed lambda-calculus, first-order logic corresponds to dependent types, second-order logic corresponds to polymorphic types, sequent calculus is related to explicit substitution, etc. The isomorphism has many aspects, even at the syntactic level: formulas correspond to types, proofs correspond to terms, provability corresponds to inhabitation, proof normalization corresponds (...) to term reduction, etc. But there is more to the isomorphism than this. For instance, it is an old idea---due to Brouwer, Kolmogorov, and Heyting---that a constructive proof of an implication is a procedure that transforms proofs of the antecedent into proofs of the succedent; the Curry-Howard isomorphism gives syntactic representations of such procedures. The Curry-Howard isomorphism also provides theoretical foundations for many modern proof-assistant systems (e.g. Coq). This book give an introduction to parts of proof theory and related aspects of type theory relevant for the Curry-Howard isomorphism. It can serve as an introduction to any or both of typed lambda-calculus and intuitionistic logic. Key features - The Curry-Howard Isomorphism treated as common theme - Reader-friendly introduction to two complementary subjects: Lambda-calculus and constructive logics - Thorough study of the connection between calculi and logics - Elaborate study of classical logics and control operators - Account of dialogue games for classical and intuitionistic logic - Theoretical foundations of computer-assisted reasoning · The Curry-Howard Isomorphism treated as the common theme. · Reader-friendly introduction to two complementary subjects: lambda-calculus and constructive logics · Thorough study of the connection between calculi and logics. · Elaborate study of classical logics and control operators. · Account of dialogue games for classical and intuitionistic logic. · Theoretical foundations of computer-assisted reasoning. (shrink)
The apparent tension between the moral codes of the Old and New Testaments constitutes a perennial problem for Christian ethics. Scholars who have taken this problem seriously have often done so in ways that presume sharp discontinuity between the Testaments. They then proceed to devise a system for identifying what is or is not relevant today, or what pertains to this or that particular social sphere. John Howard Yoder brings fresh perspectives to this perennial problem by refuting the presumption (...) of intratestamental discontinuity. Throughout multiple scattered works on the Old Testament, Yoder offers a coherent and provocative narration that culminates in the way of Christ and establishes the ethical continuity of the entire biblical canon. This essay presents the basic parameters of Yoder's Old Testament narration, suggests points where revision is needed, and highlights several implications for social ethics. (shrink)