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Single Idea 16878

[filed under theme 2. Reason / E. Argument / 6. Conclusive Proof ]

Full Idea

It is so important, if we are to have a clear insight into what is going on, for us to be able to recognise the premises of every inference which occurs in a proof and the law of inference in accordance with which it takes place.

Gist of Idea

We must be clear about every premise and every law used in a proof

Source

Gottlob Frege (Logic in Mathematics [1914], p.212)

Book Ref

Frege,Gottlob: 'Posthumous Writings', ed/tr. Hermes/Long/White etc [Blackwell 1979], p.212


A Reaction

Teachers of logic like natural deduction, because it reduces everything to a few clear laws, which can be stated at each step.


The 8 ideas with the same theme [securely establishing a result by precise defined steps]:

Proof reveals the interdependence of truths, as well as showing their certainty [Euclid, by Frege]
Proof moves from agreed premises to a non-evident inference [Sext.Empiricus]
Leibniz is inclined to regard all truths as provable [Leibniz, by Frege]
Proof aims to remove doubts, but also to show the interdependence of truths [Frege]
We must be clear about every premise and every law used in a proof [Frege]
Anything which must first be proved is of little value [Nietzsche]
A successful proof requires recognition of truth at every step [Dummett]
Proof shows that it is true, but also why it must be true [Mayberry]