Causality is the relationship between an event (the cause) and a second event (the effect), where the second event is understood as a consequence of the first. The philosophical treatment of causality extends over millennia, stretches back at least to Aristotle.
- Cause means
- (a) in one sense, that as the result of whose presence something comes into being—e.g., the bronze of a statue and the silver of a cup, and the classes which contain these [i.e., the material cause];
- (b) in another sense, the form or pattern; that is, the essential formula and the classes which contain it—e.g. the ratio 2:1 and number in general is the cause of the octave—and the parts of the formula [i.e., the formal cause].
- (c) The source of the first beginning of change or rest; e.g. the man who plans is a cause, and the father is the cause of the child, and in general that which produces is the cause of that which is produced, and that which changes of that which is changed [i.e., the efficient cause].
- (d) The same as "end"; i.e. the final cause; e.g., as the "end" of walking is health. For why does a man walk? "To be healthy," we say, and by saying this we consider that we have supplied the cause [the final cause].
- (e) All those means towards the end which arise at the instigation of something else, as, e.g., fat-reducing, purging, drugs and instruments are causes of health; for they all have the end as their object, although they differ from each other as being some instruments, others actions [i.e., necessary conditions].
- Causa latet: vis est notissima.
- The cause is hidden, but the result is known.
- Ovid, Metamorphoses, IV. 287. in Hoyt's New Cyclopedia Of Practical Quotations (1922), p. 91.
- Felix qui potuit rerum cognoscere causas.
- Happy the man who has been able to learn the causes of things.
- Virgil, Georgics (c. 29 BC), II, 490. in Hoyt's New Cyclopedia Of Practical Quotations (1922), p. 91.
Modern history, until 20th century
- Since therefore ‘tis possible for all objects to become causes or effects to each other, it may be proper to fix some general rules, by which we may know when they really are so.
- (1) The cause and effect must be contiguous in space and time.
- (2) The cause must be prior to the effect.
- (3) There must be a constant union betwixt the cause and effect. ‘Tis chiefly this quality, that constitutes the relation.
- (4) The same cause always produces the same effect, and the same effect never arises but from the same cause. This principle we derive from experience, and is the source of most of our philosophical reasonings. For when by any clear experiment we have discovered the causes or effects of any phaenomenon, we immediately extend our observation to every phenomenon of the same kind, without waiting for that constant repetition, from which the first idea of this relation is deriv’d.
- (5) There is another principle, which hangs upon this, viz. that where several different objects produce the same effect, it must be by means of some quality, which we discover to be common amongst them. For as like effects imply like causes, we must always ascribe the causation to the circumstance, wherein we discover the resemblance.
- (6) The following principle is founded on the same reason. The difference in the effects of two resembling objects must proceed from that particular, in which they differ. For as like causes always produce like effects, when in any instance we find our expectation to be disappointed, we must conclude that this irregularity proceeds from some difference in the causes.
- (7) When any object encreases or diminishes with the encrease or diminution of its cause, ‘tis to be regarded as a compounded effect, deriv’d from the union of the several different effects, which arise from the several different parts of the cause. The absence or presence of one part of the cause is here suppos’d to be always attended with the absence or presence of a proportionable part of the effect. This constant conjunction sufficiently proves, that the one part is the cause of the other. We must, however, beware not to draw such a conclusion from a few experiments. A certain degree of heat gives pleasure; if you diminish that heat, the pleasure diminishes; but it does not follow, that if you augment it beyond a certain degree, the pleasure will likewise augment; for we find that it degenerates into pain.
- (8) The eighth and last rule I shall take notice of is, that an object, which exists for any time in its full perfection without any effect, is not the sole cause of that effect, but requires to be assisted by some other principle, which may forward its influence and operation. For as like effects necessarily follow from like causes, and in a contiguous time and place, their separation for a moment shews, that these causes are not compleat ones.
- David Hume (1739-40) A Treatise of Human Nature. Book 1: Of the understanding/Part III. Sect. XV: Rules by which to judge of causes and effects.
- If reason (I mean abstract reason, derived from inquiries a priori) be not alike mute with regard to all questions concerning cause and effect, this sentence at least it will venture to pronounce, That a mental world, or universe of ideas, requires a cause as much, as does a material world, or universe of objects; and, if similar in its arrangement, must require a similar cause. For what is there in this subject, which should occasion a different conclusion or inference? In an abstract view, they are entirely alike; and no difficulty attends the one supposition, which is not common to both of them.
- David Hume (1779) Dialogues concerning Natural Religion. Philo to Cleanthes, Part IV
- To all facts there are laws,
The effect has its cause, and I mount to the cause.
- Owen Meredith (Lord Lytton), Lucile (1860), Part II, Canto III, Stanza 8. in Hoyt's New Cyclopedia Of Practical Quotations (1922), p. 91.
- Ask you what provocation I have had?
The strong antipathy of good to bad.
- Alexander Pope (1688–1744), Epilogue to Satires, Dialogue 2, line 205. in Hoyt's New Cyclopedia Of Practical Quotations (1922), p. 91.
- Your cause doth strike my heart.
- Find out the cause of this effect,
Or rather say, the cause of this defect,
For this effect defective comes by cause.
- God befriend us, as our cause is just!
- Mine's not an idle cause.
- Quantum mechanics is certainly imposing. But an inner voice tells me that it is not yet the real thing. The theory says a lot, but does not really bring us any closer to the secret of the "old one." I, at any rate, am convinced that He does not throw dice.
- Albert Einstein (1926) in letter to Max Born (4 December 1926); The Born-Einstein Letters (translated by Irene Born) (Walker and Company, New York, 1971) ISBN 0-8027-0326-7.
- Einstein himself used variants of this quote at other times. For example, in a 1943 conversation with William Hermanns recorded in Hermanns' book Einstein and the Poet, Einstein said: "As I have said so many times, God doesn't play dice with the world." (p. 58)
- Principle of causality is fundamental to human thinking, and it has been observed experimentally that this assumption leads to complex hypothesis formation by human subjects attempting to solve comparatively simple problems involving a causal randomly generated events