Hume's Scepticism and the Science of Human Nature

Paul Stanistreet

• Publisher: Routledge
• Year: 2017
• ISBN:
  9781351929387
• Edition: 1
• Topic: Philosophy
• Subtopic: Philosophy History & Theory

This book explores the relationship between Hume's sceptical philosophy and his Newtonian ambition of founding a science of human nature. Assessing both received and 'new' readings of Hume's philosophy, Stanistreet offers a line of interpretation which, he argues, makes sense of many of the apparent conflicts and paradoxes in Hume's work and describes how well-known controversies concerning Hume's thinking about causation, induction and the external world can be resolved. Stainstreet argues that Hume's notorious sceptical arguments are not the episodic outbursts of an unsystematic philosopher, but emerge as part of his attempt to provide science and philosophy with grounds which face up to and withstand the scepticism to which reflective thinkers are naturally prone. Offering important new contributions to Hume scholarship, this book also surveys and assesses the new research responsible for the recent sea-change in thinking about Hume. It offers an accessible overview of these developments while suggesting significant revisions to current readings of Hume's philosophy.

Chapter 1
Science and the Study of Human Nature

Hume describes A Treatise of Human Nature as ‘an Attempt to introduce the Experimental Method of Reasoning into Moral Subjects’ (T.xi). In his introduction to the work, he gives a ringing, though not unqualified, endorsement of the scientific method, insisting, in terms typical of much mid-eighteenth century philosophy, upon the value of observation and experience. Commentators have tended to identify Hume’s understanding of the ‘experimental method’ of the sciences with what he understood of Newton’s methodological views. There remains good reason, despite some recent hints at revisionism,¹ to think that Newton provided Hume with the paradigm for explanatory adequacy in science. Hume sets out to investigate the few general principles of human nature in much the same way as Newton had explained the phenomena of motion in terms of three general principles. His Treatise offers its readers a new theory of human nature, treating events in the mind as wholly natural occurrences, the general principles of which can be investigated on a scientific basis. Human beings are part of the natural order, and can be examined by the same procedures used by science in examining the rest of nature. Hume, however, has little to say, directly, at least, about what makes one scientific explanation better or more complete than another, or what the limits are within which such theorising ought to take place. He tells us far less than we would wish about the nature of the general ‘laws and forces’ (E.14) he takes science to be investigating, or about how those laws and forces relate to the phenomena which they are intended to explain. He does, however, have a number of general methodological aims and constraints in mind, which, I believe, implicitly guide and drive his own attempts at scientific theorising. The general features of scientific activity which Hume isolates are alone enough to merit his description as a Newtonian methodologist. There may be good reason to revise our picture of Hume’s Newtonianism, but the true picture, as I see it, places Newton still more pivotally at the heart of Hume’s putative ‘science of man’ (T.xvi), guiding, for the most part, Hume’s understanding of what a good or adequate explanation is in science.

In his introduction to the Treatise, Hume complains of the disorderly and disputatious condition of philosophy, a condition which, he suggests, can be cured only by a science of human nature which does for the human or moral sciences what Newton had done for the natural sciences. Hume has often been read as taking Newtonian science to consist purely in the compilation of digests or natural histories of phenomena, mere catalogues of natural regularities.² He is supposed to have made the observability of a cause a necessary condition for its inclusion in a scientific theory. According to one commentator, empirical science, to Hume, ‘is the discovery that things in fact behave in certain ways’, and, furthermore, in Hume’s view, ‘it is not our incapacity which prevents us from discovering ultimate causes, but the fact that there are no such causes to discover’.³ To give the cause of an event just is to state the observable regularity under which it is to be subsumed. For Hume, on this view, it is the regularities alone that are real. This leaves Hume in the embarrassing position of seeming to both endorse and repudiate a methodological outlook which, with Newton, strives to go beyond the natural phenomena in explaining them. Such a view of Hume can and ought to be resisted. I believe that Hume aimed to develop a theory of human nature similar, in substance, if not in style, to the theories of body advanced by Newton and Boyle. Human nature, Hume thought, is to be studied and explained in much the same way as these scientists had studied and explained other parts of nature. This, for Hume, meant going beyond the mere description of natural phenomena to the explanation of them. A close reading of the key texts reveals not only the care with which Hume attended to and appreciated Newton’s writings on method, but the respects in which Hume, perhaps rightly, reckoned himself a more thoroughgoing and consistent Newtonian than Newton himself.

The Accurate Anatomy of Human Nature

In the sections to follow, I examine Hume’s methodological views in detail. Since much of this discussion will be comparative, it is necessary to begin by outlining the principal theses and motivations of Hume’s theory of science. Hume gives his least-guarded presentation of his views on scientific method and its application to the moral sciences in the introduction to the Treatise. His remarks are to be borne in mind in examining the arguments and conclusions of his theory of human nature. The imperfect and unsettled condition of the sciences is to be dealt with not by abstruse metaphysical reasoning but by a scientific study of our own natures. The experimental study of human nature provides the basis not only for investigating the general principles of mind, but for the improvement and refinement of the existing sciences. It seems evident, Hume writes, that all the sciences are to some degree dependent on the ‘science of man’, since ‘they lie under the cognizance of men, and are judged of by their powers and faculties’ (T.xv). We will better understand the scope and limitations of the natural sciences once we understand the limitations of the human powers and faculties we employ in them. The only sure foundation which we can give to the study of these powers must itself ‘be laid on experience and observation’ (T.xvi). Only by putting aside the search for the ultimate causes of phenomena, and building upon the safe foundation of scientific method, can we hope to arrive at the general principles of human nature, and develop what Hume terms ‘a compleat system of the sciences’ (ibid.).

It is important to note that, for Hume, experience and observation do not provide us with foundations in the sense in which Descartes looked to offer indubitable metaphysical foundations, axiomatic first principles, for a science consisting wholly of ‘certain and evident cognition’.⁴ A search for foundations such as these, is, for Hume, as misguided as it is hopeless. The goal of science is not to make intelligible the ultimate nature of the universe. Any attempt to determine the essence of mind or matter is bound to falter, and ought ‘at first to be rejected as presumptuous and chimerical’ (T.xvii). Natural philosophy, and Newtonian mechanics, in particular, had attained its success not by attempting to determine the ultimate nature of matter, but by proceeding from careful experiments and observation of phenomena to increasingly general, though indefinitely revisable, conclusions (ibid.). The most perfect natural philosophy ‘only staves off our ignorance a little longer’ (E.31). Hume’s new foundation is to consist not in self-evident first principles, but in the application of the experimental method of the natural sciences to human nature.

Hume thought of mental phenomena as natural events, the laws and principles of which could be investigated from ‘a cautious observation of human life’ (T.xix). The scientific method had already yielded impressive results in the natural sciences, and similarly striking discoveries were to be expected from the application of the same method to the moral sciences, the subject matter of the science of man. Moral philosophy differs significantly from natural philosophy, in Hume’s view, only in taking the exclusive concerns of human beings as its special subject matter. The complete set of the moral sciences, according to Hume, consists of ‘Logic, Morals, Criticism, and Politics’ (T.xvi), although it is with his logic, his account of the ‘principles and operations of our reasoning faculty, and the nature of our ideas’ (T.xv), that he seems most concerned. It is, Hume says, ‘impossible to tell what changes and improvements we might make in these sciences were we thoroughly acquainted with the extent and force of human understanding, and cou’d explain the nature of the ideas we employ, and of the operations we perform in our reasonings’ (ibid.). Hume’s aim in Book I of the Treatise is to plot the limits of human understanding, in the hope of making us ‘perfectly satisfied in the main of our ignorance’ (T.xviii). He was critical of those philosophers who failed to discern the limits of their own powers, and sought, in his own critical work, to undermine them. Nothing is more certain, Hume writes, ‘than that despair has almost the same effect upon us with enjoyment, and that we are no sooner acquainted with the impossibility of satisfying any desire, than the desire itself vanishes’ (ibid.). The intensely sceptical arguments of Book I appear as steps in a general argument the chief aim of which is to satisfy us as to the limits within which scientific reasoning must work. Hume’s logic sets the scene for the other parts of his account of human conduct and the passions in the later books of the Treatise (T.646). He means to provide his readers with the self-assurance they will need to accompany him in the Newtonian investigations to follow. The examination of human understanding will, Hume anticipates, lead to a reform of scientific method, correcting previous excesses, and making the science of man ‘much superior in utility to any other of human comprehension’ (T.xix). Science can only stand to benefit from the accurate discernment of its own limitations. Hume spends much of Book I campaigning against the false and inflated claims made on behalf of human reason. Having ‘fully explain’d the nature of our judgment and understanding’, Hume is, at the end of Book I, ready to return ‘to a more close examination of our subject, and to proceed in the accurate anatomy of human nature’ (T.263).

There was, however, a special difficulty facing practitioners of Hume’s new science. Moral philosophy, Hume says, has ‘this peculiar disadvantage, which is not found in natural, that in collecting its experiments, it cannot make them purposely, with premeditation, and after such a manner as to satisfy itself concerning every particular difficulty which may arise’ (T.xviii–xix). To know the effects of one body upon another in a given circumstance, one has only to place them in that particular situation, and observe what follows. But should one attempt to clear up some doubt in moral philosophy, by putting oneself in the circumstance to be considered, it is evident, writes Hume, that ‘this reflection and premeditation would so disturb the operation of my natural principles, as must render it impossible to form any just conclusion from the phenomenon’ (T.xix). Hume’s science of man is not to involve laboratory work or direct experiments of the sort characteristic of the experimental natural sciences. Moral scientists must look to the uninfluenced behaviour of others, caught up in the ordinary course of their lives, for their data. We must, Hume tells us, ‘glean up our experiments’ from a broad reflection on human life, taking them ‘as they appear in the common course of the world, by men’s behaviour in company, in affairs, and in their pleasures’ (ibid.). By cautiously and judiciously collecting and comparing his experiments, the scientist of human nature can reasonably hope to found a science which is the equal, in certainty and scope, and the superior in utility, of the natural sciences.

The ultimate nature of mind being as little known to us as that of body, the moral scientist labours under no special difficulty in being ignorant of the ‘true springs and causes of phenomena’.⁵ He or she must proceed on the basis of careful and exact experiments, and the observation of particular effects, and not pretended conjecture as to ‘the ultimate original qualities of human nature’ (T.xvii). The experimental science of man must, following the example of the natural sciences, endeavour to render its principles as universal as possible by tracing its experiments ‘to the utmost, and explaining all effects from the simplest and fewest causes’ (ibid.). Hume saw quite clearly that natural scientists, such as Newton, had gained their success by seeking to determine the general ‘laws and forces’ by which, for example, ‘the revolutions of the planets are governed and directed’ (E.14). Forces had been used with regard to other parts of nature to explain phenomena as diverse as simple chemical reactions and the motion of the tides. There is no reason, Hume supposes, ‘to despair of equal success in our enquiries concerning the mental powers and economy, if prosecuted with equal capacity and caution’ (ibid.). Newton describes his own experimental programme in the preface to the Principia (1687) as ‘from the phenomena of motions to investigate the forces of nature, and then from these forces to demonstrate the other phenomena’.⁶ Hume seeks, in a similar vein, to explain the ‘operations of our reasoning faculty’ (T.xix) in terms of the fewest number of psychological general causes (E.30), controlled by laws from which other psychological phenomena can be demonstrated.

Hume makes clear, in his History of England, the nature of the debt he believed philosophy owed to Newton. While Newton ‘seemed to draw off the veil from some of the mysteries of Nature, he showed at the same time the imperfections of the mechanical philosophy; and thereby referred her ultimate secrets to that obscurity, in which they ever and ever will remain’.⁷ Newton is concerned n...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• Preface
• Introduction
• 1 Science and the Study of Human Nature
• 2 Ideas and Association
• 3 Causality, Reason and Causal Inference
• 4 Hume and the New Hume
• 5 Hume’s Scepticism Regarding the Senses
• 6 Hume’s True Philosophy and Reid’s Common Sense
• Conclusion
• Bibliography
• Index