Concept

Law of thought

Overview

philosophical axiomatisation

Overview adapted from Wikipedia (CC BY-SA 4.0; see the article history for authors).

Possible passages

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1. What is termed the ultimate incompressibility of Matter, is an admitted law of thought. Though it is possible to imagine a piece of matter to be compressed without limit, yet however small the bulk to which we conceive it reduced, it is impossible to conceive it reduced into nothing.

   Herbert Spencer, First Principles

   States what Law of thought is; opens on Law of thought.

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2. We wish, as it were, to see the matter double, first in its immediacy, and secondly in its ground, where it is no longer immediate. This is the plain meaning of the law of sufficient ground, as it is called; it asserts that things should essentially be viewed as mediated. The manner in which Formal Logic establishes this law of thought, sets a bad example to other sciences. Formal Logic asks these sciences not to…

   Georg Wilhelm Friedrich Hegel, The Logic of Hegel

   States what Law of thought is; names Law of thought twice.

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3. We noted in the preceding chapter the three principles commonly called 'laws of thought'. The view which led to their being so named is a natural one, but there are strong reasons for thinking that it is erroneous. Let us take as an illustration the law of contradiction. This is commonly stated in the form 'Nothing can both be and not be', which is intended to express the fact that nothing can at once have and not…

   Bertrand Russell, The Problems of Philosophy

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Philosophers who discussed Law of thought

• Parmenides

Related ideas

• Principle of sufficient reason
• Gottfried Wilhelm Leibniz
• Philosophy
• Law of identity
• Idealism
• Intuitionistic logic
• Law of noncontradiction
• Law of excluded middle
• Liar paradox
• Logical conjunction
• Propositional logic
• Anti-psychologism
• Sir William Hamilton, 9th Baronet
• Principle of bivalence
• Principia Mathematica
• Singular term
• Bernard Bolzano
• Theorem
• Susan Haack
• Wilhelm Wundt
• Double negation
• Many-valued logic
• George Boole
• Logical truth

Place in the tradition

Part of Paraconsistent logic.

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