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

necessity and causation

arises entirely from the uniformity observable in the operations of

nature, where similar objects are constantly conjoined together, and the

mind is determined by custom to infer the one from the appearance of the

other. These two circumstances form the whole of that necessity, which

we ascribe to matter. Beyond the constant conjunction of similar

objects, and the consequent inference from one to the other, we have

no notion of any necessity or connexion.

 

If it appear, therefore, that all mankind have ever allowed, without any

doubt or hesitation, that these two circumstances take place in the

voluntary actions of men, and in the operations of mind; it must follow,

that all mankind have ever agreed in the doctrine of necessity, and that

they have hitherto disputed, merely for not understanding each other.

 

65. As to the first circumstance, the constant and regular conjunction

of similar events, we may possibly satisfy ourselves by the following

considerations. It is universally acknowledged that there is a great

uniformity among the actions of men, in all nations and ages, and that

human nature remains still the same, in its principles and operations.

The same motives always produce the same actions. The same events follow

from the same causes. Ambition, avarice, self-love, vanity, friendship,

generosity, public spirit: these passions, mixed in various degrees, and

distributed through society, have been, from the beginning of the world,

and still are, the source of all the actions and enterprises, which have

ever been observed among mankind. Would you know the sentiments,

inclinations, and course of life of the Greeks and Romans? Study well

the temper and actions of the French and English: You cannot be much

mistaken in transferring to the former most of the observations which

you have made with regard to the latter. Mankind are so much the same,

in all times and places, that history informs us of nothing new or

strange in this particular. Its chief use is only to discover the

constant and universal principles of human nature, by showing men in all

varieties of circumstances and situations, and furnishing us with

materials from which we may form our observations and become acquainted

with the regular springs of human action and behaviour. These records of

wars, intrigues, factions, and revolutions, are so many collections of

experiments, by which the politician or moral philosopher fixes the

principles of his science, in the same manner as the physician or

natural philosopher becomes acquainted with the nature of plants,

minerals, and other external objects, by the experiments which he forms

concerning them. Nor are the earth, water, and other elements, examined

by Aristotle, and Hippocrates, more like to those which at present lie

under our observation than the men described by Polybius and Tacitus are

to those who now govern the world.

 

Should a traveller, returning from a far country, bring us an account of

men, wholly different from any with whom we were ever acquainted; men,

who were entirely divested of avarice, ambition, or revenge; who knew no

pleasure but friendship, generosity, and public spirit; we should

immediately, from these circumstances, detect the falsehood, and prove

him a liar, with the same certainty as if he had stuffed his narration

with stories of centaurs and dragons, miracles and prodigies. And if we

would explode any forgery in history, we cannot make use of a more

convincing argument, than to prove, that the actions ascribed to any

person are directly contrary to the course of nature, and that no human

motives, in such circumstances, could ever induce him to such a conduct.

The veracity of Quintus Curtius is as much to be suspected, when he

describes the supernatural courage of Alexander, by which he was hurried

on singly to attack multitudes, as when he describes his supernatural

force and activity, by which he was able to resist them. So readily and

universally do we acknowledge a uniformity in human motives and actions

as well as in the operations of body.

 

Hence likewise the benefit of that experience, acquired by long life and

a variety of business and company, in order to instruct us in the

principles of human nature, and regulate our future conduct, as well as

speculation. By means of this guide, we mount up to the knowledge of

men’s inclinations and motives, from their actions, expressions, and

even gestures; and again descend to the interpretation of their actions

from our knowledge of their motives and inclinations. The general

observations treasured up by a course of experience, give us the clue of

human nature, and teach us to unravel all its intricacies. Pretexts and

appearances no longer deceive us. Public declarations pass for the

specious colouring of a cause. And though virtue and honour be allowed

their proper weight and authority, that perfect disinterestedness, so

often pretended to, is never expected in multitudes and parties; seldom

in their leaders; and scarcely even in individuals of any rank or

station. But were there no uniformity in human actions, and were every

experiment which we could form of this kind irregular and anomalous, it

were impossible to collect any general observations concerning mankind;

and no experience, however accurately digested by reflection, would ever

serve to any purpose. Why is the aged husbandman more skilful in his

calling than the young beginner but because there is a certain

uniformity in the operation of the sun, rain, and earth towards the

production of vegetables; and experience teaches the old practitioner

the rules by which this operation is governed and directed.

 

66. We must not, however, expect that this uniformity of human actions

should be carried to such a length as that all men, in the same

circumstances, will always act precisely in the same manner, without

making any allowance for the diversity of characters, prejudices, and

opinions. Such a uniformity in every particular, is found in no part of

nature. On the contrary, from observing the variety of conduct in

different men, we are enabled to form a greater variety of maxims, which

still suppose a degree of uniformity and regularity.

 

Are the manners of men different in different ages and countries? We

learn thence the great force of custom and education, which mould the

human mind from its infancy and form it into a fixed and established

character. Is the behaviour and conduct of the one sex very unlike that

of the other? Is it thence we become acquainted with the different

characters which nature has impressed upon the sexes, and which she

preserves with constancy and regularity? Are the actions of the same

person much diversified in the different periods of his life, from

infancy to old age? This affords room for many general observations

concerning the gradual change of our sentiments and inclinations, and

the different maxims which prevail in the different ages of human

creatures. Even the characters, which are peculiar to each individual,

have a uniformity in their influence; otherwise our acquaintance with

the persons and our observation of their conduct could never teach us

their dispositions, or serve to direct our behaviour with regard

to them.

 

67. I grant it possible to find some actions, which seem to have no

regular connexion with any known motives, and are exceptions to all the

measures of conduct which have ever been established for the government

of men. But if we would willingly know what judgement should be formed

of such irregular and extraordinary actions, we may consider the

sentiments commonly entertained with regard to those irregular events

which appear in the course of nature, and the operations of external

objects. All causes are not conjoined to their usual effects with like

uniformity. An artificer, who handles only dead matter, may be

disappointed of his aim, as well as the politician, who directs the

conduct of sensible and intelligent agents.

 

The vulgar, who take things according to their first appearance,

attribute the uncertainty of events to such an uncertainty in the causes

as makes the latter often fail of their usual influence; though they

meet with no impediment in their operation. But philosophers, observing

that, almost in every part of nature, there is contained a vast variety

of springs and principles, which are hid, by reason of their minuteness

or remoteness, find, that it is at least possible the contrariety of

events may not proceed from any contingency in the cause, but from the

secret operation of contrary causes. This possibility is converted into

certainty by farther observation, when they remark that, upon an exact

scrutiny, a contrariety of effects always betrays a contrariety of

causes, and proceeds from their mutual opposition. A peasant can give no

better reason for the stopping of any clock or watch than to say that it

does not commonly go right: But an artist easily perceives that the same

force in the spring or pendulum has always the same influence on the

wheels; but fails of its usual effect, perhaps by reason of a grain of

dust, which puts a stop to the whole movement. From the observation of

several parallel instances, philosophers form a maxim that the connexion

between all causes and effects is equally necessary, and that its

seeming uncertainty in some instances proceeds from the secret

opposition of contrary causes.

 

Thus, for instance, in the human body, when the usual symptoms of health

or sickness disappoint our expectation; when medicines operate not with

their wonted powers; when irregular events follow from any particular

cause; the philosopher and physician are not surprised at the matter,

nor are ever tempted to deny, in general, the necessity and uniformity

of those principles by which the animal economy is conducted. They know

that a human body is a mighty complicated machine: That many secret

powers lurk in it, which are altogether beyond our comprehension: That

to us it must often appear very uncertain in its operations: And that

therefore the irregular events, which outwardly discover themselves, can

be no proof that the laws of nature are not observed with the greatest

regularity in its internal operations and government.

 

68. The philosopher, if he be consistent, must apply the same reasoning

to the actions and volitions of intelligent agents. The most irregular

and unexpected resolutions of men may frequently be accounted for by

those who know every particular circumstance of their character and

situation. A person of an obliging disposition gives a peevish answer:

But he has the toothache, or has not dined. A stupid fellow discovers an

uncommon alacrity in his carriage: But he has met with a sudden piece of

good fortune. Or even when an action, as sometimes happens, cannot be

particularly accounted for, either by the person himself or by others;

we know, in general, that the characters of men are, to a certain

degree, inconstant and irregular. This is, in a manner, the constant

character of human nature; though it be applicable, in a more particular

manner, to some persons who have no fixed rule for their conduct, but

proceed in a continued course of caprice and inconstancy. The internal

principles and motives may operate in a uniform manner, notwithstanding

these seeming irregularities; in the same manner as the winds, rain,

clouds, and other variations of the weather are supposed to be governed

by steady principles; though not easily discoverable by human sagacity

and enquiry.

 

69. Thus it appears, not only that the conjunction between motives and

voluntary actions is as regular and uniform as that between the cause

and effect in any part of nature; but also that this regular conjunction

has been universally acknowledged among mankind, and has never been the

subject of dispute, either in philosophy or common life. Now, as it is

from past experience that we draw all inferences concerning the future,

and as we conclude that objects will always be conjoined together which

we find to have always been conjoined; it may seem