Category: Logica Docens
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Paradox and Contradiction
A form of words can be paradoxical but not contradictory, e.g., "Most people want to become old, but few want to be old." The expression is paradoxical, and therein lies its literary charm, but the thought is non-contradictory. The thought, expressed non-paradoxically, is: Most want to live a long time, but few if any want…
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Is Assertion External or Internal to Logic? A Note on Irad Kimhi
The main point of Peter Geach's paper, "Assertion" (Logic Matters, Basil Blackwell, 1972, pp. 254-269) is what he calls the Frege point: A thought may have just the same content whether you assent to its truth or not; a proposition may occur in discourse now asserted, now unasserted, and yet be recognizably the same proposition.…
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Does the Validity of an Argument Depend on the Order of its Premises?
Suppose you have a valid argument. Can you render the argument invalid by changing the display order of the premises? I should think never. The Dark Ostrich, however, offers the following putative counterexample. He says he got it from Sainsbury; I should like to see a reference. And if there is a literature on this,…
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The Two Opposites of ‘Nothing’ and the Logical Irreducibility of Being (2018 Version)
This entry is part of the ongoing debate with the Opponent a. k. a. the Dark Ostrich. It is interesting that 'nothing' has two opposites. One is 'something.' Call it the logical opposite. The other is 'being.' Call it the ontological opposite. Logically, 'nothing' and 'something' are interdefinable quantifiers: D1. Nothing is F =df it is not the case that something is…
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Singular Existence and Quantification
For Tim M. who wants to discuss this topic with me. ComBox open. ……………………. Singular existence is the existence of particular individuals. It is the existence attributed by a use of a singular sentence such as 'Max exists,' where 'Max' is a proper name. A standard way to conceptualize singular existence, deriving from Quine and…
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Ambiguity, Vagueness, Generality, Disambiguation
Ambiguity. A property of linguistic expressions, primarily. An expression is ambiguous if it has two or more distinct meanings. Back in the day a guy asked me, "Where's your head, man?" I thought he was inquiring into my psychological state, but he merely needed to relieve himself. 'Head' is ambiguous. In its nautical use it…
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The Function-Argument Schema in the Analysis of Propositions, Part II
A second installment from the Ostrich of London. Another difficulty with the function-argument theory is staring us in the face, but generally unappreciated for what it is. As Geach says, the theory presupposes an absolute category-difference between names and predicables, which comes out in the choice of ‘fount’ [font] for the schematic letters corresponding to…
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The Function-Argument Schema in the Analysis of Propositions
The Ostrich of London sends the following to which I add some comments in blue. Vallicella: ‘One of Frege's great innovations was to employ the function-argument schema of mathematics in the analysis of propositions’. Peter Geach (‘History of the Corruptions of Logic’, in Logic Matters 1972, 44-61) thinks it actually originated with Aristotle, who suggests (Perihermenias 16b6)…
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Logical Form, Equivocation, and Propositions
Ed Buckner wants to re-fight old battles. I'm game. The following post of his, reproduced verbatim, just appeared at Dale Tuggy's site: The concept of logical form is essential to any discussion of identity, and hence to any discussion of the Trinity. Here is a puzzle I have been discussing with the famous Bill Vallicella for many…
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Why Be Consistent? Three Types of Consistency
A reader inquires: This idea of the necessity to be consistent seems to be the logician's "absolute," as though being inconsistent was the most painful accusation one could endure. [. . .] What rule of life says that one must be absolutely consistent in how one evaluates truth? It is good to argue from first…
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The ‘Is’ of Identity and the ‘Is’ of Predication: Contra Sommers
Dedication: To Bill Clinton who taught us that much can ride on what the meaning of 'is' is. ……………… The Opponent 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 is but fallout from an antecedent decision to…
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Generic Statements
Statements divide into the singular and the general. General statements divide into the universal, the particular, and the generic. Generic statements are interesting not only to the logician and linguist and philosopher but also to critics of ideology and conservative critics of leftist ideology critique. For example, leftists will find something 'ideological' about the generic…
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‘Women are Better at Looking After Children’
The Opponent supplies the above-captioned sentence for analysis. He reports that a female family member was widely defriended (unfriended?) on Facebook for agreeing that it is true. Of course the sentence is true as anyone with common sense and experience of life knows. It is an example of a generic statement or generic generalization. It…
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The Two Opposites of ‘Nothing’ and the Logical Irreducibility of Being
This entry is part of the ongoing debate with the Opponent. It is interesting that 'nothing' has two opposites. One is 'something.' Call it the logical opposite. The other is 'being.' Call it the ontological opposite. Logically, 'nothing' and 'something' are interdefinable quantifiers: D1. Nothing is F =df It is not the case that something is F.…
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The Discursive Framework, Logic, and Whether the Via Negativa is the Path to Nowhere
The Historian of Logic comments: It seems to me that what you call the ‘Discursive Framework’ is what I and others call ‘logic’, and that it reflects a Kantian view of logic that prevailed before Russell and Frege, namely that logic reflects the ‘laws of thought’ only. Are you mooting the possibility of beings which…