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Single Idea 4633
[filed under theme 2. Reason / B. Laws of Thought / 3. Non-Contradiction
]
Full Idea
Anyone who denies the principle of non-contradiction simultaneously affirms it; it cannot be rationally criticised, because it is presupposed by all rationality.
Gist of Idea
You cannot rationally deny the principle of non-contradiction, because all reasoning requires it
Source
J Baggini / PS Fosl (The Philosopher's Toolkit [2003], §1.12)
Book Ref
Baggini,J and Fosl,P.S.: 'The Philosopher's Toolkit' [Blackwells 2003], p.37
A Reaction
Nietzsche certainly wasn't afraid to ask why we should reject something because it is a contradiction. The 'logic of personal advantage' might allow logical contradictions.
The
18 ideas
from J Baggini / PS Fosl
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4582
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Basic beliefs are self-evident, or sensual, or intuitive, or revealed, or guaranteed
[Baggini /Fosl]
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4584
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The problem of induction is how to justify our belief in the uniformity of nature
[Baggini /Fosl]
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4583
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How can an argument be good induction, but poor deduction?
[Baggini /Fosl]
|
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4629
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Consistency is the cornerstone of rationality
[Baggini /Fosl]
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4632
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'Natural' systems of deduction are based on normal rational practice, rather than on axioms
[Baggini /Fosl]
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4631
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In ideal circumstances, an axiom should be such that no rational agent could possibly object to its use
[Baggini /Fosl]
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4633
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You cannot rationally deny the principle of non-contradiction, because all reasoning requires it
[Baggini /Fosl]
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4634
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Abduction aims at simplicity, testability, coherence and comprehensiveness
[Baggini /Fosl]
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4635
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Dialectic aims at unified truth, unlike analysis, which divides into parts
[Baggini /Fosl]
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4637
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To see if an explanation is the best, it is necessary to investigate the alternative explanations
[Baggini /Fosl]
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4638
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The principle of bivalence distorts reality, as when claiming that a person is or is not 'thin'
[Baggini /Fosl]
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4639
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Leibniz's Law is about the properties of objects; the Identity of Indiscernibles is about perception of objects
[Baggini /Fosl]
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4640
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If identity is based on 'true of X' instead of 'property of X' we get the Masked Man fallacy ('I know X but not Y')
[Baggini /Fosl, by PG]
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4643
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The Principle of Sufficient Reason does not presuppose that all explanations will be causal explanations
[Baggini /Fosl]
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4644
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A proposition such as 'some swans are purple' cannot be falsified, only verified
[Baggini /Fosl]
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4646
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Is 'events have causes' analytic a priori, synthetic a posteriori, or synthetic a priori?
[Baggini /Fosl]
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4645
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'A priori' does not concern how you learn a proposition, but how you show whether it is true or false
[Baggini /Fosl]
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4647
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'I have the same car as you' is fine; 'I have the same fiancée as you' is not so good
[Baggini /Fosl]
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