Jacques Maritain Center : History of Philosophy / by William Turner


So far the history of the philosophy of the eighteenth century has been the story of the empirical attempt to solve the Cartesian problem by reducing mind to matter, and of the idealistic attempt to solve the same problem by reducing matter to mind. There remains one more phase of eighteenth century speculation, namely, Hume's answer to the Cartesian problem, if indeed it may be called an answer, since it is rather a denial of the reason for proposing such a problem at all. For, instead of trying to untie what may be called the Gordian knot of post-Cartesian speculation, Hume cut the knot by denying the substantial existence of mind and matter.


Life. David Hume was born at Edinburgh in 1711. After an unsuccessful attempt to fit himself for the profession of law, he decided to take up the study of philosophy and literature. During the years 1734 to 1737, which he spent in France, he wrote his Treatise on Human Nature. The work, he says, "fell dead-born from the press, without reaching such distinction as even to excite a murmur among the zealots." Later, he recast the first book of the Treatise into his Enquiry concerning Human Understanding, the second book into his Dissertation on the Passions, and the third into his Enquiry concerning the Principles of Morals. His Essays, Moral, Political, and Literary, which were published at Edinburgh in 1742, met a favorable reception. In 1747 he accompanied a military embassy to the courts of Vienna and Turin, and again in 1763 he accompanied the English ambassador to the court of Versailles, where he remained until 1766. During the interval he had held the office of keeper of the Advocates' Library at Edinburgh, and had begun the publication of his History of England. In 1767 he was made under-secretary of state in the Foreign Office. In 1769 he returned to Edinburgh, and died there in 1776.

Sources. In addition to the works already mentioned Hume wrote a Natural History of Religion and Dialogues concerning Natural Religion. The standard edition of flume's philosophical works is that of Green and Grosse, 4 vols., London, 1874, reprinted 1889-1890. The student may be referred to Huxley's Hume (English Men of Letters series, 1879), to Knight's Hume (Blackwood's Philosophical Classics, 1886), and to the Introduction to Green and Grosse's edition of Hume's Works.


Starting Point. Hume's starting point is that of the empiricist, and his conception of the method of philosophical procedure is that of the critical philosopher. In the Introduction to the Treatise on Human Nature he writes, "To me it seems evident that, the essence of the mind being equally unknown to us with that of external bodies, it must be equally impossible to form any notion of its powers and qualities otherwise than from careful and exact experiments . . . it is certain we cannot go beyond experience."{1} The critical element appears when, in this same Introduction and in the opening paragraphs of the Enquiry concerning Human Understanding, he reduces all philosophy to the study of human nature, basing the study of human nature on the observation of mental phenomena and "an exact analysis of the powers and capacity" of the mind.

Analysis of Mind. According to Hume, the mind is its contents. His analysis of the mind is, therefore, merely an inventory of the contents of the mind, or of perceptions. In Hume's philosophy, perception is synonymous with state of consciousness, the term being equivalent to the Cartesian thought and to the idea of Locke and Berkeley.

Hume divides perceptions into two classes: impressions, which are defined as the more lively perceptions experienced when we hear, see, will, love, etc. (perceptions therefore, include passions and emotions as well as sensations), and ideas or thoughts, which are faint images of impressions.{2} As to the innateness of impressions and ideas, Hume says that, if by innate we mean contemporary with our birth, the dispute seems to be frivolous; but if by innate we understand what is original or copied from no precedent perception, then we may assert that all our impressions are innate and our ideas not innate.{3} When, therefore, Hume speaks of memory, imagination, ideas of relation, abstract ideas, etc., he is speaking of mental faculties and states which are ultimately reducible to sense-faculties and to the impressions of the senses.

What, then, are the objects of our impressions? Hume answers that we do not perceive substance nor qualities, but only our own subjective states. "'T is not our body we perceive when we regard our limbs and members, but certain impressions which enter by the senses. The last words seem to indicate a belief in an external cause of our impressions, and, indeed, Hume is not at all consistent in his subjectivism; for he admits, in at least one passage, the possibility of our impressions either arising from the object, or being produced by the creative power of the mind, or being derived from the Author of our being.

The denial of the substantiality of the mind is Hume's most distinctive contribution to psychology. It is, he says, successive perceptions only that constitute the mind. The substantiality of the ego is a delusion; what we call mind is simply "a heap or collection of different perceptions united together by certain relations, and supposed, though falsely, to be endowed with simplicity and identity."{4} Thus did Hume complete the work of empiricism. Locke reasoned away everything except the primary qualities of bodies and the unknown substratum (substance) in which they adhere; Berkeley showed that even the substance and primary qualities of bodies might be reasoned away, and now Hume applies the same solvent to the substance of mind itself, and leaves nothing but phenomena.

If the substantial nature of the ego is a delusion, immortality is not a datum of reason. We are not surprised, therefore, to find that in the essay On the Immortality of the Soul, Hume, after examining the arguments in favor of immortality, which arguments he divides into metaphysical, moral, and physical, concludes that "it is the gospel, and the gospel alone, that has brought life and immortality to light."

Analysis of Causation. Quite in keeping with Hume's denial of substance is his analysis of causation into a succession of phenomena. All our ideas, he teaches, are connected either by resemblance, contiguity in time, contiguity in space, or causality. Causality, then, is merely a relation between our ideas; but is it an a priori relation, and if not, whence and how does it arise?

The first of these questions Hume answers in the negative. He formulates the principle of causality as follows: Whatever event has a beginning must have a cause.{5} He maintains that "the knowledge of this relation (causality) is not, in any instance, attained by reasonings a priori; but arises entirely from experience, when we find that any particular objects are constantly conjoined with each other.{6} All distinct ideas are separable from each other, and, as the ideas of cause and effect are evidently distinct, 't will be easy for us to conceive any object as non-existent this moment, and existent the next, without conjoining to it the distinct idea of a cause or producing principle."{7} The argument, as Huxley remarks,{8} "is of the circular sort, for the major premise that all distinct ideas are separable in thought, assumes the question at issue."

The axiom of causality, therefore, comes from experience. But, Hume observes, one instance does not constitute sufficient experimental evidence of the causal connection of two phenomena. When, however, "one particular series of events has always, in all instances, been conjoined with another, we make no longer any scruple in foretelling one on the appearance of the other. . . . We then call the one cause and the other effect. We suppose that there is some connexion between them: some power in the one by virtue of which it infallibly produces the other. . . . But there is nothing in a number of instances different from every single instance which is supposed to be exactly similar, except only that after a repetition of similar instances the mind is carried by habit, upon the appearance of one event, to expect its usual attendant and to believe that it will exist."{9} There is, therefore, no real dependence of effect on cause, no ontological nexus, but merely a psychological one, an expectation arising from habit or custom.

Hume, indeed, admits that, in addition to the notion of sequence of phenomena, there is in our concept of causality the idea of something resident in the cause -- a power, force, or energy -- which produces the effect. When, however, he comes to analyze this notion of power, he finds it to be merely a projection of the subjective feeling of effort into the phenomenon, which is the invariable antecedent. "No animal can put external bodies in motion without the sentiment of a nisus, or endeavor, and every animal has a sentiment or feeling from the stroke or blow of an external object that is in motion. . We consider only the constant experienced conjunction of the events, and as we feel the customary connection between the ideas, we transfer that feeling to the objects."{10}

From the empirical viewpoint, Hume's analysis of the principle of causality is thorough. If there is in the mind no power superior to sensation and reflection, no faculty by which we are enabled to abstract from the contingent data of sense the necessary elements of intellectual thought, then all the axioms of science, the axiom of causality included, are mere associations of sense-impressions. But the empirical standpoint is erroneous; in this, as in other instances, empiricism stops where the real problem of philosophy begins, as is evident from the fact that, while Hume succeeds in showing that one event is connected with another in our past experience, neither he nor any other empiricist has shown why we are entitled to expect that events which have been connected in the past will be connected in the future. Empiricism can show a connectio facti, but it cannot show a connectio juris, between antecedent and consequent, between cause and effect.

Ethics. Hume's ethical system is a development of the fundamental doctrine of the English ethical schools of the eighteenth century. He restricts the rôle of reason as a moral criterion and develops the doctrine that moral distinctions are determined by our sense of the agreeable and the disagreeable. Abstract distinctions, mere rational intuitions or inferences, leave us perfectly indifferent as to action, so long as they fail to acquire an emotional value through some relation to the passions and ultimately to the feeling of the agreeableness or disagreeableness of the action to be performed. "Nothing but a sentiment can induce us to give the preference to the beneficial and useful tendencies over pernicious ones. This sentiment is, in short, nothing but sympathy."{11} The following is the ultimate analysis of moral value: "No man is absolutely indifferent to the happiness and misery of others. The first has a natural tendency to give pleasure; the second, pain. This every one may find in himself. It is not probable that these principles can be resolved into principles more simple and universal, whatever attempts may be made to that purpose."{12}

Historical Position. Hume's philosophy is summed up in the words pan-phenomenalism and scepticism. He reduced mind as well as matter to mere phenomena, and denied the ontological nexus between cause and effect. He maintained that there is no permanent, immutable element in the world of our experience, and that there is no valid principle which can justify metaphysical speculation concerning the world beyond our experience. It was this total subversion of the necessary and universal that awoke Kant from his dogmatic slumber, and gave rise in Scotland to the movement in favor of the philosophy of common sense.

It will be necessary, before entering on the study of these reactions against Hume, to give a brief sketch of what is known as the German illumination -- the transition from Leibniz to Kant.

{1} Works, I, 308. References are to Green and Grosse's edition, 1890.

{2} Op. cit., IV, 13.

{3} Note to the second edition of the Enquiry, Works, IV, 17.

{4} Cf. Works, I, 534.

{5} Cf. Huxley's Hume, p. 120. In Hume's Treatise on Human Nature, p. 381, Occurs the form, "Whatever has a beginning has also a cause of existence."

{6} Works, IV, 24.

{7} Op. cit., I, 381.

{8} Hume, p. 122.

{9} Works, IV, 62.

{10} Op. cit., IV, 62, a.

{11} Cf. Falckenberg, op. cit., p. 190, English trans., p. 233.

{12} Works, IV, 208, a.

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