Maverick Philosopher

Footnotes to Plato from the foothills of the Superstition Mountains

Category: Logica Docens

  • Hegel, Booze, and Fruit

    A Substack quickie.

  • Russell’s Paradox Explained

    A reader asked for an explanation of Russell's Paradox. My pleasure. 1. From a contradiction, anything follows. Ex contradictione quod libet. Another way of putting it would be to say that every argument having contradictory premises is valid. 'Valid' is a technical term. An argument A is valid =df no argument of A's form has…

  • Reader Requests Advice re: Learning Basics of Philosophical Argumentation

    A New Zealand reader writes,   I was hoping if you are able to provide me with some guidance regarding where to begin learning the basics of philosophical arguments. I’ve been trying to understand how to evaluate political and theological debates for awhile, but despite my interest I often find them go away over my…

  • A Difference Between Plausibility and Probability

    The plausibility of a conjunctive proposition is that of the least plausible of its conjuncts. Not so for the probability of a conjunctive proposition. This point is made by Nicholas Rescher in his entry 'Plausibility' in the Oxford Companion to Philosophy. Exercise for the reader: give examples.

  • Ambiguity, Vagueness, Generality, Disambiguation

    Top o' the Stack Some distinctions needed for intellectual hygiene.

  • The Difference between Posing and Begging a Question

    I found the nifty graphic below over at Flood's place.  It is a pithy and pictorial presentation of a point I have been hammering away at online for the last twenty years. Here is a Substack hammer-job. Some say we should give up the fight and let the forces of linguistic decadence obliterate the distinction…

  • The Ersatz Eternity of the Past: Denied by Lukasiewicz!

    The Pole denies the actuality of the past and in consequence thereof the ersatz eternity or accidental necessity (necessitas per accidens) of the past. Quasi-literary Preamble: What has been, though it needn't have been, always will have been.  What time has mothered, no future time can destroy.   What you were and that you were stand forever…

  • Logic Quiz: Is the Argument Below Specious or Sound?

    1) What I know cannot be otherwise: if I know that p, then p cannot be false. Therefore 2) If I know that a man is walking, then 'a man is walking' cannot be false. Therefore 3) If  I know that a man is walking, then it is necessarily true that a man is walking.…

  • Argumentative Circles and their Diameters: More on Presuppositionalism

    The day before yesterday, re: presuppositionalism, I wrote: We need to bear in mind  that arguments have premises and that no argument can prove its own premises. An argument of the form p therefore p is an argument valid in point of logical form in which premise and conclusion are identical, but no one will take an argument…

  • Retorsion Revisited: How Far Does it Reach and What Does it Prove?

    Retorsion (retortion) is the philosophical procedure whereby one attempts to establish a thesis by uncovering a performative inconsistency in anyone who denies it. It is as old as Aristotle and has been put to use by philosophers as diverse as Transcendental Thomists and Ayn Rand and her followers. Retorsion is something like an ad hominem tu quoque except…

  • Nota Notae Est Nota Rei Ipsius, Kant, and the Ontological Argument

    This is a re-post, redacted and re-thought, from 22 July 2011. I dust it off because something caught my eye the other morning in the Translator's Introduction to Kant's Logic. Robert S. Hartman and Wolfgang Schwarz tell us that for Kant the principle of all inference or mediate judgment is the rule Nota notae est…

  • Counterexamples and Outliers

    An exception to a universal generalization is a counterexample that refutes the generalization. All you need is one. Generic statements cannot, however, be similarly refuted. 'Nuns don't smoke cigars' is a generic statement. If you turn up a nun who smokes cigars I won't take you to have refuted the generic statement. I'll dismiss the…

  • Questions about a Lukasiewicz Passage

    E. B. sent this: http://www.logicmuseum.com/wiki/Logical_form_(Lukasiewicz) “When, for instance, asserting the implication 'If all philosophers are men, then all philosophers are mortal' you would also assert as second premiss the sentence 'Every philosopher is a man', you could not get from these premisses the conclusion 'All philosophers are mortal', because you would have no guarantee that…

  • Syntactic and Semantic Validity Again

    Edward sends this interesting example: Omnis homo est mortalis Socrates is a man Sokrates ist sterblich Semantically valid, but not syntactically? No, syntactically valid because the argument instantiates a valid argument-form, to wit: Every F is a Ga is an FThereforea is a G. Validity is a matter of form. An argument is valid if…

  • Syntactic versus Semantic Validity

    Consider the argument:    Bill is a brother   —–   Bill is a sibling. Is this little argument valid or invalid?  It depends on what we mean by 'valid.' Intuitively, the argument is valid in the following sense: D1. An argument is valid if and only if it is impossible that its premise(s) be true and its…