Maverick Philosopher

Footnotes to Plato from the foothills of the Superstition Mountains

Category: Logica Docens

  • Logical Versus Metaphysical Modality

    A Pakistani reader inquires: This is a query which I hope you can answer. Is there such a distinction as 'logical contingency' vs 'metaphysical contingency', and 'logical necessity' vs 'metaphysical necessity'? And if there is, can you explain it? Thank you. A short answer first.  Yes, there are these distinctions.  They amount to a distinction…

  • Should We Abandon the Deep Problems for Problems Amenable to Solution?

    UPDATE: London Ed does an excellent job of misunderstanding the following post.  Bad comments incline me to keep my ComBox closed.  But his is open. Fred Sommers' "Intellectual Autobiography" begins as follows: I did an undergraduate major in mathematics at Yeshiva College and went on to graduate studies in philosophy at Columbia University in the…

  • David Brightly’s Weblog and a Punctilio Anent Predication and Inclusion

    The unduly modest David Brightly has begun a weblog entitled tillyandlola, "scribblings of no consequence."   In a recent post he criticizes my analysis of the invalidity of the argument: Man is a species; Socrates is a man; ergo, Socrates is a species.  I claimed that the argument equivocates on 'is.'  In the major premise, 'is'…

  • Arguments and Proofs in Philosophy

    London Ed writes: Philosophers always refer to their arguments as 'arguments' and never as 'proofs'. This is because there is nothing in the entire, nearly three thousand year history of philosophy that would count as a proof of anything. Nothing. This obiter dictum illustrates how, by exaggerating and saying something that is strictly false, one…

  • Transitivity of Predication?

    I dedicate this post to London Ed, who likes sophisms and scholastic arcana. Consider these two syllogistic arguments: A1. Man is an animal; Socrates is a man; ergo, Socrates is an animal.A2. Man is a species; Socrates is a man; ergo, Socrates is a species. The first argument is valid.  On one way of accounting for its…

  • Frege Meets Aquinas: A Passage from De Ente et Essentia

    Here is a passage from Chapter 3 of Thomas Aquinas, On Being and Essence (tr. Robert T. Miller, emphasis added): The nature, however, or the essence thus understood can be considered in two ways. First, we can consider it according to its proper notion, and this is to consider it absolutely. In this way, nothing is…

  • Politicization and Hypostatization

    Something that in its very nature is political cannot be politicized.  (Example here.)  Similarly, that which in its mode of being is substantial cannot be hypostatized or reified.  Hypostatization is illicit reification.

  • Closure: Some Mathematical and Philosophical Examples

    A reader asks, "What is meant by 'closure' or 'closed under'? I've heard the terms used in epistemic contexts,  but I've not been able to completely understand them." Let's start with some mathematical   examples. The natural numbers are closed under the operation of addition. This means that the result of adding any two natural numbers…

  • On the Expressibility of ‘Something Exists’

    Surely this is a valid and sound argument: 1. Stromboli exists.Ergo2. Something exists. Both sentences are true; both are meaningful; and the second follows from the first.  How do we translate the argument into the notation of standard first-order predicate logic with identity? Taking a cue from Quine we may formulate (1) as 1*.  For…

  • The Stromboli Puzzle

    Here is another puzzle London Ed may enjoy.  Is the following argument valid or invalid: An island volcano exists.Stromboli is an island volcano.ErgoStromboli exists. The argument appears valid, does it not?  But it can't be valid if it falls afoul of the dreaded quaternio terminorum, or 'four-term fallacy.'  And it looks like it does.  On the…

  • Ockham and Induction

    Ed of Beyond Necessity reports that he has translated some chapters on induction from Ockham's Summa Logicae. He goes on: Ockham says that induction "is a progression from singulars to the universal", which is pretty much the modern understanding of the term. That is not wrong, but it is not quite right either.  On a…

  • Morning Star and Evening Star

    London Ed of Beyond Necessity does a good job patiently explaining the 'morning star' – 'evening star' example to one of his uncomprehending readers.  But I don't think Ed gets it exactly right.  I quibble with the following: Summarising:(1) The sentence “the morning star is the evening star” has informational content.(2) The sentence “the morning star…

  • Composition: Formal or Informal Fallacy?

    Although the fallacy of composition is standardly classified as an informal fallacy, I see  it is a formal fallacy, one rooted in logical form. Let W be any sort of whole (whether set, mereological sum, aggregate, etc.) Suppose each of the proper parts (if any) of W has some property P (or, for the nominalistically inclined, satisfies…

  • Neologisms, Paleologisms, and Grelling’s Paradox

    'Neologism' is not a new word, but an old word. Hence, 'neologism' is not a neologism. 'Paleologism' is not a word at all; or at least it is not listed in the Oxford English Dictionary. But it ought to be a word, so I hereby introduce it. Who is going to stop me? Having read…

  • The ‘Is’ of Identity and the ‘Is’ of Predication

    Bill Clinton may have brought the matter to national attention, but philosophers have long appreciated that much can ride on what the meaning of 'is' is.  Edward of London has a very good post in which he raises the question whether the standard analytic distinction between the 'is' of identity and the 'is' of predication…