scholarly journals In defence of logical nominalism: reply to Leftow

2010 ◽  
Vol 46 (3) ◽  
pp. 311-330
Author(s):  
RICHARD SWINBURNE

AbstractThis paper defends (especially in response to Brian Leftow's recent attack) logical nominalism, the thesis that logically necessary truth belongs primarily to sentences and depends solely on the conventions of human language. A sentence is logically necessary (that is, a priori metaphysically necessary) iff its negation entails a contradiction. A sentence is a posteriori metaphysically necessary iff it reduces to a logical necessity when we substitute for rigid designators of objects or properties canonical descriptions of the essential properties of those objects or properties. The truth-conditions of necessary sentences are not to be found in any transcendent reality, such as God's thoughts. ‘There is a God’ is neither a priori nor a posteriori metaphysically necessary; God is necessary in the sense that His existence is not causally contingent on anything else.

Author(s):  
Colin McGinn

This chapter explores philosophical issues in metaphysics. It begins by distinguishing between de re and de dicto necessity. All necessity is uniformly de re; there is simply no such thing as de dicto necessity. Indeed, in the glory days of positivism, all necessity was understood as uniformly the same: a necessary truth was always an a priori truth, while contingent truths were always a posteriori. The chapter then assesses the concept of antirealism. Antirealism is always an error theory: there is some sort of mistake or distortion or sloppiness embedded in the usual discourse. The chapter also considers paradoxes, causation, conceptual analysis, scientific mysteries, the possible worlds theory of modality, the concept of a person, the nature of existence, and logic and propositions.


Author(s):  
Alan Sidelle

Necessary truths have always seemed problematic, particularly to empiricists and other naturalistically-minded philosophers. Our knowledge here is a priori - grounded in appeals to what we can imagine or conceive (or can prove on that basis) - which seems hard to reconcile with such truths being factual, short of appealing to some peculiar faculty of a priori intuition. And what mysterious extra feature do necessary truths possess which makes their falsity impossible? Conventionalism about necessity claims that necessary truths obtain by virtue of rules of language, such as that ‘vixen’ means the same as ‘female fox’. Because such rules govern our descriptions of all cases - including counterfactual or imagined ones - they generate necessary truths (‘All vixens are foxes’), and our a priori knowledge is just knowledge of word meaning. Opponents of conventionalism argue that conventions cannot ground necessary truths, particularly in logic, and have also challenged the notion of analyticity (truth by virtue of meaning). More recent claims that some necessary truths are a posteriori have also fuelled opposition to conventionalism.


2012 ◽  
Vol 4 (2) ◽  
pp. 1-18 ◽  
Author(s):  
Richard Swinburne

A logically impossible sentence is one which entails a contradiction, a logically necessary sentence is one whose negation entails a contradiction, and a logically possible sentence is one which does not entail a contradiction. Metaphysically impossible, necessary and possible sentences are ones which become logically impossible, necessary, or possible by substituting what I call informative rigid designators for uninformative ones. It does seem very strongly that a negative existential sentence cannot entail a contradiction, and so ‘there is a God’ cannot be a metaphysically necessary truth. If it were such a truth, innumerable other sentences which seem paradigm examples of logically possible sentences, such as ‘no one knows everything’ would turn out to be logically impossible. The only way in which God could be a logically necessary being is if there were eternal necessary propositions independent of human language or God’s will, such that the proposition that there is no God would entail – via propositions inaccessible to us – a contradiction. But if there were such propositions, God would have less control over the universe than he would have otherwise.


Philosophy ◽  
2008 ◽  
Vol 83 (2) ◽  
pp. 179-191 ◽  
Author(s):  
Stephen K. McLeod

AbstractBy the lights of a central logical positivist thesis in modal epistemology, for every necessary truth that we know, we know it a priori and for every contingent truth that we know, we know it a posteriori. Kripke attacks on both flanks, arguing that we know necessary a posteriori truths and that we probably know contingent a priori truths. In a reflection of Kripke's confidence in his own arguments, the first of these Kripkean claims is far more widely accepted than the second. Contrary to received opinion, the paper argues, the considerations Kripke adduces concerning truths purported to be necessary a posteriori do not disprove the logical positivist thesis that necessary truth and a priori truth are co-extensive.


2020 ◽  
pp. 86-92
Author(s):  
Paul Boghossian ◽  
Timothy Williamson

This chapter replies to Boghossian’s defence of the a priori–a posteriori distinction against the arguments for its shallowness in?The Philosophy of Philosophy. In particular, it shows how to understand the example of an unorthodox thinker who is linguistically competent with conjunction but refuses to treat the rule of conjunction elimination as logically valid. It also rebuts Boghossian’s charge of circularity against the account of knowledge of metaphysical modality in terms of the cognitive capacities required to assess ordinary counterfactual conditionals. For the explanation of knowledge of logic and mathematics, the key significance is emphasized of the distinction between knowing the truth of what is in fact a necessary truth and knowing that it is necessary.


Author(s):  
Heinrich Schepers ◽  
Giorgio Tonelli ◽  
Rudolf Eisler
Keyword(s):  
A Priori ◽  

1994 ◽  
Vol 11 (4) ◽  
pp. 475-503
Author(s):  
Masudul Alum Choudhury

Is it the realm of theoretical constructs or positive applications thatdefines the essence of scientific inquiry? Is there unison between thenormative and the positive, between the inductive and deductivecontents, between perception and reality, between the micro- andmacro-phenomena of reality as technically understood? In short, isthere a possibility for unification of knowledge in modernist epistemologicalcomprehension? Is knowledge perceived in conceptionand application as systemic dichotomy between the purely epistemic(in the metaphysically a priori sense) and the purely ontic (in thepurely positivistically a posteriori sense) at all a reflection of reality?Is knowledge possible in such a dichotomy or plurality?Answers to these foundational questions are primal in order tounderstand a critique of modernist synthesis in Islamic thought thathas been raging among Muslim scholars for some time now. Theconsequences emanating from the modernist approach underlie muchof the nature of development in methodology, thinking, institutions,and behavior in the Muslim world throughout its history. They arefound to pervade more intensively, I will argue here, as the consequenceof a taqlid of modernism among Islamic thinkers. I will thenargue that this debility has arisen not because of a comparativemodem scientific investigation, but due to a failure to fathom theuniqueness of a truly Qur'anic epistemological inquiry in the understandingof the nature of the Islamic socioscientific worldview ...


2019 ◽  
Vol 11 ◽  
pp. 51-64
Author(s):  
M. LE MOAL

Les systèmes d’information géographique (SIG) sont devenus incontournables dans la gestion des réseaux d’eau et d’assainissement et leur efficacité repose en très grande partie sur la qualité des données exploitées. Parallèlement, les évolutions réglementaires et les pratiques des utilisateurs augmentant notamment les échanges d’informations renforcent le rôle central des données et de leur qualité. Si la plupart des solutions SIG du marché disposent de fonctions dédiées à la qualification de la qualité des données, elles procèdent de la traduction préalable de spécifications des données en règles informatiques avant de procéder aux tests qualitatifs. Cette approche chronophage requiert des compétences métier. Pour éviter ces contraintes, Axes Conseil a élaboré un procédé de contrôle des données SIG rapide et accessible à des acteurs métier de l’eau et de l’assainissement. Plutôt qu’une lourde approche de modélisation a priori, le principe est de générer un ensemble d’indicateurs explicites facilement exploitables a posteriori par les acteurs du métier. Cette approche offre une grande souplesse d’analyse et ne nécessite pas de compétences informatiques avancées.


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