← Excerpt
Custom as Guide
David Hume
An Enquiry Concerning Human Understanding

Hume identifies custom as the essential guide of human life, without which we would be unable to act or reason beyond our immediate memory.

...y depend. Not to mention, that, to a young beginner, the general observations and maxims occur not always on the proper occasions, nor can be immediately applied with due calmness and distinction. The truth is, an unexperienced reasoner could be no reasoner at all, were he absolutely unexperienced; and when we assign that character to any one, we mean it only in a comparative sense, and suppose him possessed of experience, in a smaller and more imperfect degree.
Custom, then, is the great guide of human life. It is that principle alone which renders our experience useful to us, and makes us expect, for the future, a similar train of events with those which have appeared in the past. Without the influence of custom, we should be entirely ignorant of every matter of fact beyond what is immediately present to the memory and senses. We should never know how to adjust means to ends, or to employ our natural powers in the production of any effect. There would be an end at once of all action, as well as of the chief part of speculation.
37. But here it may be proper to remark, that though our conclusions from experience carry us beyond our memory and senses, and assure us of matters of fact which happened in the most distant places and most remote ages, yet some fact must always be present to the senses or memory, from which we may first proceed in drawing these conclusions. A man, who should find in a desert country the remains of pompous buildings, would conclude that the country had, in ancient times, been cultivated by ci...
4

David Hume

An Enquiry Concerning Human Understanding

Nature's Pre-established Harmony

Hume elaborates on the parent text by describing a 'pre-established harmony' between nature and our ideas, effected by custom. He reinforces custom's necessity for human subsistence and the regulation of conduct, directly extending the claim that custom makes experience useful and guides our expectations.

...t is there in this whole matter to cause such a strong conception, except only a present object and a customary transition to the idea of another object, which we have been accustomed to conjoin with the former? This is the whole operation of the mind, in all our conclusions concerning matter of fact and existence; and it is a satisfaction to find some analogies, by which it may be explained. The transition from a present object does in all cases give strength and solidity to the related idea.
Here, then, is a kind of pre-established harmony between the course of nature and the succession of our ideas; and though the powers and forces, by which the former is governed, be wholly unknown to us; yet our thoughts and conceptions have still, we find, gone on in the same train with the other works of nature. Custom is that principle, by which this correspondence has been effected; so necessary to the subsistence of our species, and the regulation of our conduct, in every circumstance and occurrence of human life. Had not the presence of an object, instantly excited the idea of those objec...
Those, who delight in the discovery and contemplation of final causes, have here ample subject to employ their wonder and admiration. 45. I shall add, for a further confirmation of the foregoing theory, that, as this operation of the mind, by which we infer like effects from like causes, and vice versa, is so essential to the subsistence of all human creatures, it is not probable, that it could be trusted to the fallacious deductions of our reason, which is slow in its operations; appears...

Blaise Pascal

Pensees

Custom's Power

Pascal provides a psychological mechanism for how custom operates: it is the source of our strongest proofs by bending the 'automaton' (the unconscious mind), which persuades the intellect without conscious reasoning. This explains the underlying driver of the authority that custom holds over human belief and action.

...and internals. It raises the common people to the internal, and humbles the proud to the external; it is not perfect without the two, for the people must understand the spirit of the letter, and the learned must submit their spirit to the letter. 252 For we must not misunderstand ourselves; we are as much automatic as intellectual; and hence it comes that the instrument by which conviction is attained is not demonstrated alone. How few things are demonstrated? Proofs only convince the mind.
Custom is the source of our strongest and most believed proofs. It bends the automaton, which persuades the mind without its thinking about the matter. Who has demonstrated that there will be a to-morrow, and that we shall die? And what is more believed? It is, then, custom which persuades us of it; it is custom that makes so many men Christians; custom that makes them Turks, heathens, artisans, soldiers, etc.
(Faith in baptism is more received among Christians than among Turks.) Finally, we must have recourse to it when once the mind has seen where the truth is, in order to quench our thirst, and steep ourselves in that belief, which escapes us at every hour; for always to have proofs ready is too much trouble. We must get an easier belief, which is that of custom, which, without violence, without art, without argument, makes us believe things, and inclines all our powers to this belief, so that out...

Blaise Pascal

Pensees

Chance's Career Choice

Pascal reframes the discussion away from custom as a guide for empirical inference and toward custom as the primary determinant of social roles and professions. He argues that chance and custom, rather than nature, shape our callings in life, shifting the lens to the societal and personal implications of habitual practice.

...t make natural; there is nothing natural he may not lose. 95 Memory, joy, are intuitions; and even mathematical propositions become intuitions, for education produces natural intuitions, and natural intuitions are erased by education. 96 When we are accustomed to use bad reasons for proving natural effects, we are not willing to receive good reasons when they are discovered. An example may be given from the circulation of the blood as a reason why the vein swells below the ligature. 97
The most important affair in life is the choice of a calling; chance decides it. Custom makes men masons, soldiers, slaters. "He is a good slater," says one, and, speaking of soldiers, remarks, "They are perfect fools." But others affirm, "There is nothing great but war, the rest of men are good for nothing." We choose our callings according as we hear this or that praised or despised in our childhood, for we naturally love truth and hate folly. These words move us; the only error is in their application. So great is the force of custom that out of those whom nature has only made men, are crea...
98 Bias leading to error.--It is a deplorable thing to see all men deliberating on means alone, and not on the end. Each thinks how he will acquit himself in his condition; but as for the choice of condition, or of country, chance gives them to us. It is a pitiable thing to see so many Turks, heretics, and infidels follow the way of their fathers for the sole reason that each has been imbued with the prejudice that it is the best. And that fixes for each man his conditions of locksmith, s...

John Stewart Mill

Utilitarianism

Experience's Accumulated Wisdom

Mill offers practical guidance by stating that the tendencies of actions are learned through accumulated experience, and this experience forms the basis for both prudence and morality in life. He implies that we should rely on this collective experiential knowledge to inform our conduct.

...ch objections as this--that there is not time, previous to action, for calculating and weighing the effects of any line of conduct on the general happiness. This is exactly as if any one were to say that it is impossible to guide our conduct by Christianity, because there is not time, on every occasion on which anything has to be done, to read through the Old and New Testaments. The answer to the objection is, that there has been ample time, namely, the whole past duration of the human species.
During all that time mankind have been learning by experience the tendencies of actions; on which experience all the prudence, as well as all the morality of life, is dependent. People talk as if the commencement of this course of experience had hitherto been put off, and as if, at the moment when some man feels tempted to meddle with the property or life of another, he had to begin considering for the first time whether murder and theft are injurious to human happiness. Even then I do not think that he would find the question very puzzling; but, at all events, the matter is now done to his ha...
It is truly a whimsical supposition, that if mankind were agreed in considering utility to be the test of morality, they would remain without any agreement as to what is useful, and would take no measures for having their notions on the subject taught to the young, and enforced by law and opinion. There is no difficulty in proving any ethical standard whatever to work ill, if we suppose universal idiocy to be conjoined with it, but on any hypothesis short of that, mankind must by this time have...