An Enquiry Concerning Human Understanding, David Hume [online e book reader TXT] 📗

and involved; and

nothing can be more curious, as well as useful, than to trace, by a

variety of mediums, their equality or inequality, through their

different appearances. But as all other ideas are clearly distinct and

different from each other, we can never advance farther, by our utmost

scrutiny, than to observe this diversity, and, by an obvious reflection,

pronounce one thing not to be another. Or if there be any difficulty in

these decisions, it proceeds entirely from the undeterminate meaning of

words, which is corrected by juster definitions. That _the square of the

hypothenuse is equal to the squares of the other two sides_, cannot be

known, let the terms be ever so exactly defined, without a train of

reasoning and enquiry. But to convince us of this proposition, _that

where there is no property, there can be no injustice_, it is only

necessary to define the terms, and explain injustice to be a violation

of property. This proposition is, indeed, nothing but a more imperfect

definition. It is the same case with all those pretended syllogistical

reasonings, which may be found in every other branch of learning, except

the sciences of quantity and number; and these may safely, I think, be

pronounced the only proper objects of knowledge and demonstration.

 

132. All other enquiries of men regard only matter of fact and

existence; and these are evidently incapable of demonstration. Whatever

is may not be. No negation of a fact can involve a contradiction.

The non-existence of any being, without exception, is as clear and

distinct an idea as its existence. The proposition, which affirms it not

to be, however false, is no less conceivable and intelligible, than that

which affirms it to be. The case is different with the sciences,

properly so called. Every proposition, which is not true, is there

confused and unintelligible. That the cube root of 64 is equal to the

half of 10, is a false proposition, and can never be distinctly

conceived. But that Caesar, or the angel Gabriel, or any being never

existed, may be a false proposition, but still is perfectly conceivable,

and implies no contradiction.

 

The existence, therefore, of any being can only be proved by arguments

from its cause or its effect; and these arguments are founded entirely

on experience. If we reason a priori, anything may appear able to

produce anything. The falling of a pebble may, for aught we know,

extinguish the sun; or the wish of a man control the planets in their

orbits. It is only experience, which teaches us the nature and bounds of

cause and effect, and enables us to infer the existence of one object

from that of another[34]. Such is the foundation of moral reasoning,

which forms the greater part of human knowledge, and is the source of

all human action and behaviour.

 

[34] That impious maxim of the ancient philosopher, _Ex nihilo,

nihil fit_, by which the creation of matter was excluded,

ceases to be a maxim, according to this philosophy. Not all the

will of the supreme Being may create matter; but, for aught we

know a priori, the will of any other being might create it,

or any other cause, that the most whimsical imagination

can assign.

 

Moral reasonings are either concerning particular or general facts. All

deliberations in life regard the former; as also all disquisitions in

history, chronology, geography, and astronomy.

 

The sciences, which treat of general facts, are politics, natural

philosophy, physic, chemistry, &c. where the qualities, causes and

effects of a whole species of objects are enquired into.

 

Divinity or Theology, as it proves the existence of a Deity, and the

immortality of souls, is composed partly of reasonings concerning

particular, partly concerning general facts. It has a foundation in

reason, so far as it is supported by experience. But its best and most

solid foundation is faith and divine revelation.

 

Morals and criticism are not so properly objects of the understanding as

of taste and sentiment. Beauty, whether moral or natural, is felt, more

properly than perceived. Or if we reason concerning it, and endeavour to

fix its standard, we regard a new fact, to wit, the general tastes of

mankind, or some such fact, which may be the object of reasoning

and enquiry.

 

When we run over libraries, persuaded of these principles, what havoc

must we make? If we take in our hand any volume; of divinity or school

metaphysics, for instance; let us ask, _Does it contain any abstract

reasoning concerning quantity or number?_ No. _Does it contain any

experimental reasoning concerning matter of fact and existence?_ No.

Commit it then to the flames: for it can contain nothing but sophistry

and illusion.

 

INDEX

 

Abstraction

not source of ideas of primary qualities, 122.

 

Academic

philosophy, 34.

 

Action

and philosophy, 1, 4, 34, 128;

 

Addition

4.

Analogy

a species of, the foundation of all reasoning about matter of fact,

82;

 

Animals

the reason of, 83-85;

learn from experience and draw inferences, 83;

which can only be founded on custom, 84;

cause of difference between men and animals, 84 n.

 

Antiquity

62.

Appearances

to senses must be corrected by reason, 117.

 

A priori

25, 36 n, 89 n, 132, 132 n.

 

Aristotle

4.

Association

of ideas, three principles of, 18-19, 41-44 (v. Cause C).

 

Atheism

116.

Bacon

99.

Belief

(v. Cause C, 39-45);

and chance, 46.

 

Berkeley

really a sceptic, 122 n.

 

Bigotry

102.

Body

and soul, mystery of union of, 52;

volition and movements of, 52.

 

Real existence of (v. Scepticism, B, 118-123).

 

Cause

first (v. God, Necessity, 78-81; Providence,

102-115, 132 n).

a principle of association of ideas, 19, 43;

sole foundation of reasonings about matter of fact or real existence,

22.

A. Knowledge of Causes arises from experience not from Reason,

23-33.

 

Reasonings a priori give no knowledge of cause and effect,

23 f.;

impossible to see the effect in the cause since they are totally

different, 25;

natural philosophy never pretends to assign ultimate causes, but only

to reduce causes to a few general causes, e.g. gravity, 26;

geometry applies laws obtained by experience, 27.

 

Conclusions from experience not based on any process of the

understanding, 28;

yet we infer in the future a similar connexion between known

qualities of things and their secret powers, to that which

we assumed in the past. On what is this inference based? 29;

demonstrative reasoning has no place here, and all experimental

reasoning assumes the resemblance of the future to the past,

and so cannot prove it without being circular, 30, 32;

if reasoning were the basis of this belief, there would be no need

for the multiplication of instances or of long experience,

31;

yet conclusions about matter of fact are affected by experience even

in beasts and children, so that they cannot be founded on

abstruse reasoning, 33;

to explain our inferences from experience a principle is required of

equal weight and authority with reason, 34.

 

B. _Custom enables us to infer existence of one object from the

appearance of another_, 35-38.

 

Experience enables us to ascribe a more than arbitrary connexion to

objects, 35;

we are determined to this by custom or habit which is the great guide

of human life, 36;

but our inference must be based on some fact present to the senses

or memory, 37;

the customary conjunction between such an object and some other

object produces an operation of the soul which is as

unavoidable as love, 38;

animals also infer one event from another by custom, 82-84;

and in man as in animals experimental reasoning depends on a species

of instinct or mechanical power that acts in us unknown to

ourselves, 85.

 

C. Belief, 39-45.

Belief differs from fiction or the loose reveries of the fancy by

some feeling annexed to it, 39;

belief cannot be defined, but may be described as a more lively,

forcible, firm, steady conception of an object than can be

attained by the imagination alone, 40;

it is produced by the principles of association, viz. resemblance,

41;

contiguity, 42;

causation, 43;

by a kind of pre-established harmony between the course of nature

and our ideas, 44;

this operation of our minds necessary to our subsistence and so

entrusted by nature to instinct rather than to reasoning, 45.

 

Probability, 46-7.

 

Belief produced by a majority of chances by an inexplicable

contrivance of Nature, 46 (cf. 87-8);

probability of causes: the failure of a cause ascribed to a secret

counteracting cause, 47 (cf. 67);

it is universally allowed that chance when strictly examined is a

mere negative word, 74.

 

D. Power, 49-57.

 

Power, force, energy, necessary connexion must either be defined by

analysis or explained by production of the impression from

which they are copied, 49;

from the first appearance of an object we cannot foretell its effect:

we cannot see the power of a single body: we only see

sequence, 50.

 

Is the idea of power derived from an internal impression and is it an

idea of reflection? 51;

it is not derived, as Locke said, from reasoning about power of

production in nature, 50 n;

nor from consciousness of influence of will over bodily organs, 52;

nor from effort to overcome resistance, 52 n (cf. 60 n);

nor from influence of will over mind, 53;

many philosophers appeal to an invisible intelligent principle, to a

volition of the supreme being, and regard causes as only

occasions and our mental conceptions as revelations, 54-5;

thus diminishing the grandeur of God, 56;

this theory too bold and beyond verification by our faculties, and

is no explanation, 57;

vis inertiae, 57 n.

 

In single instances we only see sequence of loose events which are

conjoined and never connected, 58;

the idea of necessary connexion only arises from a number of similar

instances, and the only difference between such a number and

a single instance is that the former produces a habit of

expecting the usual attendant, 59, 61.

This customary transition is the impression from which we form the

idea of necessary connexion.

 

E. Reasoning from effect to cause and conversely, 105-115 (v.

Providence).

 

In arguing from effect to cause we must not infer more qualities in

the cause than are required to produce the effect, nor reason

backwards from an inferred cause to new effects, 105-8;

we can reason back from cause to new effects in the case of human

acts by analogy which rests on previous knowledge, 111-2;

when the effect is entirely singular and does not belong to any

species we cannot infer its cause at all, 115.

 

F. Definitions of Cause, 60 (cf. 74 n).

 

Ceremonies

41.

Chance

ignorance of causes, 46;

has no existence, 74 (v. Cause B).

 

Cicero

4.

Circle

in reasoning, 30.

 

Clarke

37 n.

 

Colour

peculiarity of ideas of, 16.

 

Contiguity

19, 42.

 

Contradiction

the test of demonstration, 132.

 

Contrariety

19 n.

 

Contrary

of matter of fact always possible, 21, 132.

 

Creation

132 n.

 

Criticism

132.

Cudworth

57 n, 158 n.

 

Custom

when strongest conceals itself, 24;

an ultimate principle of all conclusions from experience, 36, 127;

and belief, 39-45;

gives rise to inferences of animals, 84.

 

Definition

only applicable to complex ideas, 49;

need of, 131;

of cause, 60.

 

Demonstrative

opp. intuitive, 20;

reasoning, 30;

confined to quantity and number, 131;

impossible to demonstrate a fact since no negation of a fact can

involve a contradiction, 132.

 

Descartes

57 n.;

his universal doubt antecedent to study if strictly taken is

incurable, since even from an indubitable first