Talk:Universal instantiation

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Philosophy: Logic Mid‑importance

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Quine

I am reading Quine at the moment (quintessence, extensionalism, Reference and Modality. From this I would like to add to this article:

Universal Instantiation and Existential generalization are two aspects of a single principle, for instead of saying that '(x(x=x)' implies 'Socrates is Socrates', we could as well say that the denial 'Socrates≠Socrates' implies '(∃x(x≠x)'. The principle embodied in these two operations is the link between quantifications and the singular statements that are related to them as instances. Yet it is a principle only by courtesy. It holds only in the case where a term names and, furthermore, occurs referentially^[1].

Any ideas, remarks, or changes?

--Fan Singh Long (talk) 05:57, 6 February 2012 (UTC)[reply]

Ok, since no one has seen fit to leave any comments at all, I will edit the article now.

--Fan Singh Long (talk) 06:42, 13 February 2012 (UTC)[reply]

I see no reason for the addition. Inasmuch as it an expression of Quine's philosophical views, it is irrelevant to the article at hand, and inasmuch as it a statement of the logical rules of inference of UI and EG, it is simply superfluous. In short, it would be more appropriately included in the article on Quine.

John Aiello (talk) 04:51, 25 January 2013 (UTC)[reply]

The Quine section appears to have been lifted verbatim from one of Quine's articles. Put quotes around it, and then move it to the Quine article because it doesn't belong here. From a logical perspective what Quine observed is, assuming propositional logic and quantifier negation, you can use either Universal Instantiation or Existential Generalization to prove that the other is valid. ProfRB (talk) 20:16, 22 March 2019 (UTC)[reply]

References

^ Quine,W.V.O., Quintessence, Extensionalism, Reference and Modality, P366

Poor references

These:

1. Copi and Cohen

2. Hurley

3. Moore and Parker

4. pg. 71. Symbolic Logic; 5th ed.

cannot be acceptable references. What by Copi and Cohen, Hurley, and Moore and Parker? — Preceding unsigned comment added by 86.185.221.149 (talk) 13:56, 16 December 2013 (UTC)[reply]

[1] Quine,W.V.O., Quintessence, Extensionalism, Reference and Modality, P366

[1]