WorkDavid Hume

An Enquiry Concerning Human Understanding

The book that finally printed his case against miracles — and the one Kant read, in German, before rewriting philosophy.

by David Hume206 passages held

English, the original language, and your language

First published: 1748(aged 37)
Original language: English

Report a rights issue

Overview

In December 1737, with the Treatise almost finished, Hume told his friend Henry Home that he was cutting into the manuscript: taking out the reasoning most likely to offend religious readers, in the hope of buying the book a hearing. It bought him nothing. Eleven years later Andrew Millar published in London the material he had removed, set inside a shorter and far clearer restatement of his theory of knowledge; it appeared as Philosophical Essays concerning Human Understanding, and took the name it now carries only in the edition of 1758. Twelve sections. At the centre of them is the argument that every confident belief about matters of fact rests on experienced repetition and nothing firmer: that the sun will rise tomorrow cannot be proved, only expected, because we have never met the connection itself, merely the sequence. Two sections have no counterpart in the earlier book. One asks what weight testimony can carry when what it reports is a violation of the laws of nature, and answers that no testimony has ever been strong enough, since the witness being wrong is always the smaller wonder. The other takes apart the inference from an orderly world to a designer of it. The replies were prompt: William Adams answered the miracles argument in 1752, and John Douglas published rules for telling true miracles from false. George Campbell's book of 1762 reached Hume in manuscript; he sent back objections, and Campbell thanked him for them and softened the passages that stung. In Germany it landed differently. A translation appeared in 1755, decades before any German Treatise, and Kant, who read no English, met Hume in it; he later credited that encounter with breaking the spell of his own settled metaphysics, though which argument broke it is still disputed.

Key concepts

What is the difference between impressions and ideas?

Impressions are immediate perceptions, while ideas are weaker copies of them in thought or memory. In the Enquiry, Hume uses this distinction to test the legitimacy of philosophical concepts: a meaningful idea must ultimately trace back to some impression. If no such source can be found, the supposed concept lacks clear content and should be rejected or carefully redefined.

How do relations of ideas differ from matters of fact?

Relations of ideas are truths established by thinking alone, whereas matters of fact require experience and can always be denied without contradiction. Geometry supplies Hume's clearest example of the first kind; the claim that the sun will rise tomorrow belongs to the second. This division limits demonstrative reasoning: certainty governs definitions, not what happens in the world.

What does Hume mean by mitigated skepticism?

Mitigated skepticism limits inquiry to questions suited to human understanding and restrains conclusions that outrun experience. Hume does not recommend permanent paralysis; he accepts ordinary reasoning, science, and common life while rejecting dogmatic claims about hidden causes or ultimate reality. In Section XII, this discipline replaces speculative certainty with proportioned belief and modest expectations about what inquiry can establish.

Why does Hume distrust reports of miracles?

Hume distrusts miracle reports because testimony must overcome the uniform evidence of experience against violations of nature. A report becomes credible only when its falsehood would be even more miraculous than the event reported. Section X therefore examines witnesses, cultural credulity, and competing accounts rather than simply declaring miracles impossible; its target is the rational standard for accepting testimony.

What makes an idea philosophically meaningful for Hume?

An idea is philosophically meaningful when its contents can be specified and traced to experience, rather than left as an undefined verbal impression. Hume applies this demand to terms such as power, substance, and necessity, asking what perception supplies their meaning. The test does not end inquiry; it separates genuine questions from verbal disputes disguised as metaphysics.

Themes of the book

What this book returns to, gathered into themes and ordered by how much of the text each one occupies.

Causation, Custom, and Belief

How can experience justify the expectations that guide thought and action when it never presents necessary connection itself? The answer determines whether knowledge rests on reason, evidence, or a habit that reason cannot prove.

Hume argues that perceptions reveal one event following another, never the necessity that binds them. Against the rationalist hope that reason can establish causal laws, he traces belief in causes to custom: repeated experience trains the mind to expect one impression after another. Inductive reasoning therefore lacks demonstrative proof, yet human nature continues to rely on it. Skepticism exposes the gap between evidence and certainty without removing ordinary inquiry, prediction, or action.

belief
experience
skepticism
evidence
empiricism
habit
inference
induction
reasoning
necessity
testimony
imagination
perception
causation

Enter a dialogue

Within this work

passages held: 206
distinct concepts: 267
by passages held, corpus-wide: #344

What this book thinks together

The wheel takes this book’s leading concepts and shows how often they come up together. The wider the band between two, the more of its passages speak of both. Among them, most often together: “causation” and “induction”.

Concept co-occurrence, strongest first 8 concepts, joined by 25 pairings. 80 pairings reach beyond these concepts and are not drawn.
Concept	Paired concept	Shared passages
causation	induction	31
miracles	testimony	24
epistemology	induction	15
causation	necessity	12
causation	skepticism	12
epistemology	testimony	12
induction	skepticism	12
epistemology	skepticism	11
epistemology	miracles	10
causation	epistemology	7
human nature	induction	7
induction	necessity	7
induction	testimony	7
causation	human nature	5
skepticism	testimony	5
epistemology	human nature	4
human nature	miracles	4
human nature	necessity	4
induction	miracles	4
miracles	skepticism	4
human nature	skepticism	3
human nature	testimony	2
causation	miracles	1
causation	testimony	1
necessity	testimony	1

Works held

The author's work in order, this book marked in place. Your-language title first, the original beneath it where the two differ; side chips show which full texts are held.

1739 A Treatise of Human Nature
The quarry from which nearly everything else on this shelf was cut, and now the most read of Hume's books — which is the opposite of what he wanted.
EN
1741 Essays
Not one book but a collection under a single title, and the place on this shelf where Hume writes for the general reader — on politics, trade, taste and manners — rather than for philosophers.
EN
1748 An Enquiry Concerning Human Understanding you are here EN
1751 An Enquiry Concerning the Principles of Morals
The moral theory of the Treatise's third book, rebuilt for the readers who were never going to open the original.
EN
1752 Hume's Political Discourses
Twelve essays on money, trade, taxes, public credit and population, published in 1752 and later folded into his collected essays — economics before there was a word for it.
EN
1757 The Natural History of Religion
Written for a volume that lost two of its essays to a threatened prosecution, this one asks where religion came from rather than whether any of it is true — the historical half of a question the Dialogues take up philosophically.
EN
1779 Dialogues Concerning Natural Religion
A conversation in three voices that its author kept by him for a quarter of a century, revising it three times and letting nobody print it while he lived.
EN

— or open another of their works