Resumen
Resumen de Sistema de lógica raciocinativa e inductiva
Para quién es
For readers who love philosophy, science and the history of ideas, and enjoy following a careful argument step by step. Mill explores evidence, cause, experimental inquiry and the study of human society.
De qué trata este libro
A System of Logic, Ratiocinative and Inductive is a treatise by the English philosopher John Stuart Mill, first published in 1843. Mill wrote it to answer a plain question. How do we know that what we believe is true? He wanted a method for testing evidence that a scientist, a lawyer, a doctor or a citizen could all use.
The book was written against a background of quarrels. Many thinkers of his day held that some truths are simply known by intuition, with no need for proof. Mill thought this habit protected old prejudices from question. He set out to show that all knowledge of the world, from the laws of motion to the rules of morals, comes from experience and can be checked by it.
In this summary you will meet the book's main ideas in the order Mill gives them. You will see why he treats words and definitions first, why he says the syllogism proves nothing new, and how he describes cause. You will learn his four methods of experimental inquiry, his list of fallacies, and his hope for a science of human society. Let us begin with the aim of logic itself.
En este resumen
- 1Logic is the art of judging evidenceFree
- 2Clear words and propositions come first
- 3The syllogism proves nothing you did not know
- 4All real knowledge rests on induction from experience
- 5A cause is an unconditional invariable sequence
- 6Four methods help find causes by experiment
- 7Real causes are tangled, so reasoning must combine methods
- 8Careful classification and fallacy-spotting protect good thinking
- 9Human life can be studied by the same methods
Idea clave 1 de 9
Logic is the art of judging evidence
Mill opens by asking what logic is for. He does not treat it as a game with words. For him it is the study of the operations of the mind that help us weigh evidence, so that we can tell when a belief is well founded and when it is not.
He separates what we know directly from what we infer. We know our own sensations and feelings straight away. Almost everything else, from the weather tomorrow to the cause of a disease, is reached by reasoning from something else. If so, the quality of our reasoning decides the quality of nearly all we believe.
This puts Mill in opposition to the school of thought that says some truths are known by an inner light, beyond argument. He objects that such claims are hard to test. A person who feels certain can call that feeling a self-evident truth, and then nobody can question it. Mill sees this as a danger to science, to politics and to morals alike.
His answer is to set out a practical method. If we can state clearly how good evidence works, he argues, we can sort sound conclusions from unsound ones, whoever holds them. The standards of proof that serve in a laboratory should also serve in an argument about law or society.
For a reader today the point is direct. Before asking whether a claim is true, ask what kind of evidence could support it. Mill's whole book is an extended training in that habit, and the rest of his argument builds on this starting point.
That’s 1 of 9 key points.
The rest of the summary, written and spoken, and the whole book: free to start.
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Questions about Sistema de lógica raciocinativa e inductiva
What is A System of Logic by John Stuart Mill about?
It is a study of how we reason and how we judge evidence. Mill explains words and propositions, the limits of the syllogism, induction, cause, and methods of experiment, then applies them to the study of mind and society.
What are Mill's methods of induction?
They are four rules for finding causes by comparing cases: agreement, difference, residues and concomitant variations. Mill also describes a joint method of agreement and difference. They remain a standard way to teach how causal claims are tested.
Is A System of Logic hard to read?
Mill writes clearly, with many examples. Readers often start with the third book on induction and cause.
Why does Mill say the syllogism proves nothing new?
He argues that the general premise, such as all men are mortal, already assumes the conclusion. Real inference happens earlier, when we move from observed cases to a rule, so the syllogism only checks that we have drawn from that rule correctly.