Does philosophy—its study or practice—make us happy? Should it? The word is from Greek φιλοσοφία, philosophia, literally “love of wisdom”. Wisdom sounds good and love certainly is. And what if you were in the middle of writing one of the greatest works in the history of philosophy? That would feel good, wouldn’t it?
That was the situation the young David Hume was in as he wrote A Treatise of Human Nature, published in 1739-1740. Hume is often considered the greatest philosopher ever to write in English and the Treatise is his major work. Futhermore, Hume had a cheerful personality. Anthony Gottlieb says Hume’s “genial good humor and benign disposition should be taken into account. He had a gift for inspiring affection, even among some of his intellectual opponents.” The Dream of Enlightenment p. 197. His friend Adam Smith said “His temper seemed to be more happily balanced… than that perhaps of any other man I have ever known.” Hume was no gloomy pedant.
And so he must have been having quite a good time writing his Treatise, which he thought was very important. It would propose “a complete system of the sciences, built on a foundation almost entirely new, and the only one upon which they can stand with any security.” Treatise p. xvi. Heady stuff.
Yet as he finished the first of the three books of his Treatise, he found himself in despair, fancying himself a “strange uncouth monster.” The gap between the common sense of normal life and the conclusions compelled by his philosophy was vast. As described by Barry Stroud, Hume had reached a point of profound and incurable scepticism, feeling that
Philosophical reflection on the nature of perception inevitably leads to scepticism. It must portray our natural beliefs as unwarranted and mistaken. Even a little reflection is enough to convince us that we are much worse off in ordinary life than we unreflectively suppose. This result, however depressing, cannot be avoided by more philosophizing. There is no antidote to scepticism within philosophy… Our natural instincts do not successfully meet or resolve the sceptical doubts; they simply submerge them. Man is so constituted that he must believe, for example, in the existence of bodies, even though he cannot defend that belief with any good reasons. Nor will any amount of good reasoning free him from the sceptical doubts arising inevitably out of reflection on the grounds for that belief. Hume p. 115.
Hume concluded Book I of the Treatise,“Of the Understanding”, with a remarkable set of personal reflections on how these thoughts affected him. Hume is tempted by the philosophy of Spinal Tap: “Have a good time all of the time.” His own thinking interferes with his own good times. And yet, eventually he becomes “tired with amusement”. Even good times can get boring. Hume feels his mind become “all collected within itself.” He must mean that those old thoughts start coming back. He cannot help but be curious about matters of controversy. That’s natural too. “These sentiments spring up naturally in my present disposition; and should I endeavour to banish them, by attaching myself to any other business or diversion, I feel I should be a loser in point of pleasure; and this is the origin of my philosophy.” In the end, not doing philosophy would make life less fun.
Hume’s thoughts are worth quoting at length (here lightly edited to enhance its accessibility for the modern blog reader; we don’t read early 18th century prose very often; emphasis added). They start on page 263 of the Selby-Bigge edition of the Treatise.
SECT. VII. CONCLUSION OF THIS BOOK.
Before I launch out into those immense depths of philosophy which lie before me, I find myself inclined to stop a moment in my present station and to ponder that voyage which I have undertaken, and which undoubtedly requires the utmost art and industry to be brought to a happy conclusion. Methinks I am like a man, who having struck on many shoals, and having narrowly escaped shipwreck in passing a small frith, has yet the temerity to put out to sea in the same leaky weather-beaten vessel, and even carries  his ambition so far as to think of compassing the globe under these disadvantageous circumstances. My memory of past errors and perplexities makes me diffident for the future. The wretched condition, weakness, and disorder of the faculties I must employ in my enquiries increase my apprehensions. And the impossibility of amending or correcting these faculties reduces me almost to despair, and makes me resolve to perish on the barren rock on which I am at present rather than venture myself upon that boundless ocean, which runs out into immensity. This sudden view of my danger strikes me with melancholy. And as it is usual for that passion, above all others, to indulge itself, I cannot forbear feeding my despair with all those desponding reflections, which the present subject furnishes me with in such abundance.
I am first affrighted and confounded with that forelorn solitude, in which I am placed by my philosophy. And I fancy myself some strange uncouth monster, who not being able to mingle and unite in society has been expelled from all human commerce and left utterly abandoned and disconsolate. Fain would I run into the crowd for shelter and warmth, but cannot prevail with myself to mix when I have such deformity. I call upon others to join me, in order to make a company apart, but no one will hearken to me. Everyone keeps at a distance, and dreads that storm, which beats upon me from every side. I have exposed myself to the enmity of all metaphysicians, logicians, mathematicians, and even theologians. Can I wonder at the insults I must suffer? I have declared my disapprobation of their systems; and can I be surprised, if they should express a hatred of mine and of my person? When I look abroad, I foresee on every side dispute, contradiction, anger, calumny and detraction. When I turn my eye inward, I find nothing but doubt and ignorance. All the world conspires to oppose and contradict me. Such is my weakness, that I feel all my opinions loosen and fall of themselves, when unsupported by the  approbation of others. Every step I take is with hesitation, and every new reflection makes me dread an error and absurdity in my reasoning.
For with what confidence can I venture upon such bold enterprises, when beside those numberless infirmities peculiar to myself, I find so many which are common to human nature? Can I be sure that in leaving all established opinions I am following truth? By what criterion shall I distinguish her, even if fortune should at last guide me on her foot-steps? After the most accurate and exact of my reasonings, I can give no reason why I should assent to it. I feel nothing but a strong propensity to consider objects strongly in that view under which they appear to me. Experience is a principle which instructs me in the several conjunctions of objects for the past. Habit is another principle, which determines me to expect the same for the future. Both of them conspire to operate upon the imagination, and make me form certain ideas in a more intense and lively manner than others, which are not attended with the same advantages. Without this quality, by which the mind enlivens some ideas beyond others (which seemingly is so trivial, and so little founded on reason), we could never assent to any argument, nor carry our view beyond those few objects which are present to our senses. Nay, even to these objects, we could never attribute any existence but what was dependent on the senses. We must comprehend them entirely in that succession of perceptions which constitutes our self or person. Nay farther, even with relation to that succession, we could only admit of those perceptions which are immediately present to our consciousness. Nor could those lively images, with which the memory presents us, be ever received as true pictures of past perceptions. The memory, senses, and understanding are, therefore, all of them founded on the imagination, or the vivacity of our ideas.
No wonder a principle so inconstant and fallacious should lead us into errors when implicitly followed (as it must be) in  all its variations. It is this principle which makes us reason from causes and effects. And it is the same principle which convinces us of the continued existence of external objects when absent from the senses. But though these two operations be equally natural and necessary in the human mind, yet in some circumstances they are directly contrary. It is not possible for us to reason justly and regularly from causes and effects, and at the same time believe the continued existence of matter. How then shall we adjust those principles together? Which of them shall we prefer? Or in case we prefer neither of them, but successively assent to both, as is usual among philosophers, with what confidence can we afterwards usurp that glorious title, when we thus knowingly embrace a manifest contradiction?
This contradiction would be more excusable were it compensated by any degree of solidity and satisfaction in the other parts of our reasoning. But the case is quite contrary. When we trace human understanding to its first principles, we find it to lead us into such sentiments as seem to turn into ridicule all our past pains and industry and to discourage us from future enquiries. Nothing is more curiously enquired after by the mind of man than the causes of every phenomenon. Nor are we content with knowing the immediate causes, but push on our enquiries till we arrive at the original and ultimate principle. We would not willingly stop before we are acquainted with that energy in the cause by which it operates on its effect, that tie which connects them together, and that efficacious quality on which the tie depends. This is our aim in all our studies and reflections. How disappointed must we be when we learn that this connexion, tie, or energy lies merely in ourselves, and is nothing but that determination of the mind acquired by custom which causes us to make a transition from an object to its usual attendant and from the impression of one to the lively idea of the other? Such a discovery not  only cuts off all hope of ever attaining satisfaction, but even prevents our very wishes, since it appears that when we say we desire to know the ultimate and operating principle as something which resides in the external object, we either contradict ourselves or talk without a meaning.
Indeed, this deficiency in our ideas is not perceived in common life. Nor are we aware that in the most usual conjunctions of cause and effect we are as ignorant of the ultimate principle, which binds them together, as in the most unusual and extraordinary. But this proceeds merely from an illusion of the imagination. The question is how far we ought to yield to these illusions. This question is very difficult, and reduces us to a very dangerous dilemma, whichever way we answer it. For if we assent to every trivial suggestion of the fancy (beside that these suggestions are often contrary to each other) they lead us into such errors, absurdities, and obscurities, that we must at last become ashamed of our credulity. Nothing is more dangerous to reason than the flights of the imagination, and nothing has been the occasion of more mistakes among philosophers. Men of bright fancies may in this respect be compared to those angels, whom the scripture represents as covering their eyes with their wings. This has already appeared in so many instances that we may spare ourselves the trouble of enlarging upon it any farther.
But on the other hand, if the consideration of these instances makes us resolve to reject all the trivial suggestions of the fancy and adhere to the understanding (that is, to the general and more established properties of the imagination), even this resolution, if steadily executed, would be dangerous and attended with the most fatal consequences. For I have already shown that the understanding, when it acts alone and according to its most general principles, entirely subverts itself and leaves not the lowest degree of evidence in any proposition, either in philosophy or  common life. We save ourselves from this total scepticism only by means of that singular and seemingly trivial property of the fancy by which we enter with difficulty into remote views of things. We are not able to accompany them with so tangible an impression as we do those which are more easy and natural. Shall we then establish it as a general maxim that no refined or elaborate reasoning is ever to be received? Consider well the consequences of such a principle. By this means you cut off entirely all science and philosophy. You proceed upon one singular quality of the imagination, and by a parity of reason must embrace all of them. And you expressly contradict yourself; since this maxim must be built on the preceding reasoning, which will be allowed to be sufficiently refined and metaphysical. What path, then, shall we choose among these difficulties? If we embrace this principle, and condemn all refined reasoning, we run into the most manifest absurdities. If we reject it in favour of these reasonings, we subvert entirely human understanding. We have, therefore, no choice left but betwixt a false reason and none at all. For my part, I know not what ought to be done in the present case. I can only observe what is commonly done, which is that this difficulty is seldom or never thought of, and even where it has once been present to the mind, is quickly forgot, and leaves but a small impression behind it. Very refined reflections have little or no influence upon us. And yet we do not and cannot establish it as a rule that they ought not to have any influence, which leaves us with a dilemma. [which implies a manifest contradiction]
But what have I said here that reflections very refined and metaphysical have little or no influence upon us? This opinion I can scarce forbear retracting and condemning from my present feeling and experience. The intense view of these manifold contradictions and imperfections in human reason has so heated my brain that I am ready to reject all belief and reasoning, and can look upon no opinion even as more probable or likely than  another. Where am I, or what? From what causes do I derive my existence, and to what condition shall I return? Whose favour shall I court and whose anger must I dread? What beings surround me? and on whom have I any influence, or who has any influence on me? I am confounded with all these questions, and begin to fancy myself in the most deplorable condition imaginable, immersed in the deepest darkness and utterly deprived of the use of every member and faculty.
Most fortunately it happens that since reason is incapable of dispelling these clouds, nature herself suffices to that purpose. Nature cures me of this philosophical melancholy and delirium, either by relaxing this bent of mind or by some avocation and lively sense impression which obliterates all these chimeras. I dine, I play a game of backgammon, I converse, and am merry with my friends; and when after three or four hours’ amusement, I would return to these speculations, they appear so cold, and strained, and ridiculous, that I cannot find in my heart to enter into them any farther.
Here then I find myself absolutely and necessarily determined to live, and talk, and act like other people in the common affairs of life. But notwithstanding that my natural propensity and the course of my animal spirits and passions reduce me to this indolent belief in the general maxims of the world, I still feel such remains of my former disposition that I am ready to throw all my books and papers into the fire and resolve never more to renounce the pleasures of life for the sake of reasoning and philosophy. For those are my sentiments in that splenetic humour which governs me at present. I may—nay I must—yield to the forces of nature in submitting to my senses and understanding; and in this blind submission I show most perfectly my sceptical disposition and principles. But does it follow that I must strive against the forces of nature which lead me to indolence and pleasure; that I must  seclude myself in some measure from the commerce and society of men, which is so agreeable. Must I torture my brains with subtleties and sophistries at the very time that I cannot satisfy myself concerning the reasonableness of so painful an application, nor have any tolerable prospect of arriving by its means at truth and certainty. Under what obligation do I lie to make such an abuse of time? And to what end can it serve either for the service of mankind or for my own private interest? No. If I must be a fool, as all those who reason or believe anything certainly are, my follies shall at least be natural and agreeable. Where I strive against my inclination, I shall have a good reason for my resistance, and will no more be led a wandering into such dreary solitudes, and rough passages as I have hitherto met with.
These are the sentiments of my spleen and indolence. Indeed I must confess that philosophy has nothing to oppose to them, and expects a victory more from the returns of a serious good-humoured disposition, than from the force of reason and conviction. In all the incidents of life we ought still to preserve our scepticism. If we believe that fire warms or water refreshes, it is only because it costs us too much pains to think otherwise. Nay, if we are philosophers, it ought only to be upon sceptical principles, and from an inclination which we feel to the employing ourselves after that manner. Where reason is lively and mixes itself with some propensity, it ought to be assented to. Where it does not, it never can have any title to operate upon us.
At the time, therefore, that I am tired with amusement and company, and have indulged a reverie in my chamber or in a solitary walk by a river-side, I feel my mind all collected within itself. I am naturally inclined to carry my view into all those subjects which I have found in the course of my reading and conversation to involve so many disputes. I cannot help but have a curiosity to be  acquainted with the principles of moral good and evil, the nature and foundation of government, and the cause of those several passions and inclinations which actuate and govern me. I am uneasy to think I approve of one object and disapprove of another, call one thing beautiful and another deformed, decide concerning truth and falsehood, reason and folly, without knowing upon what principles I proceed. I am concerned for the condition of the learned world, which lies under such deplorable ignorance in all these particulars. I feel an ambition arise in me to contribute to the instruction of mankind and to acquire a name by my inventions and discoveries. These sentiments spring up naturally in my present disposition; and should I endeavour to banish them, by attaching myself to any other business or diversion, I feel I should be a loser in point of pleasure; and this is the origin of my philosophy.
But even suppose this curiosity and ambition should not transport me into speculations outside the sphere of common life, it would necessarily happen that from my very weakness I must be led into such enquiries. It is certain that superstition is much more bold in its systems and hypotheses than philosophy. While the latter contents itself with assigning new causes and principles to the phenomena which appear in the visible world, superstition opens a world of its own, and presents us with scenes, and beings, and objects, which are altogether new. Since therefore it is almost impossible for the mind of man to rest, like those of beasts, in that narrow circle of objects which are the subject of daily conversation and action, we ought only to deliberate concerning the choice of our guide, and ought to prefer that which is safest and most agreeable. And in this respect I make bold to recommend philosophy. I shall not hesitate to give it the preference to superstition in everything. For as superstition arises naturally and easily from the popular opinions of mankind, it seizes more strongly on the mind, and is  often able to disturb us in the conduct of our lives and actions. Philosophy on the contrary, if just, can present us only with mild and moderate sentiments. If false and extravagant, its opinions are merely the objects of a cold and general speculation, and seldom go so far as to interrupt the course of our natural propensities. The cynics are an extraordinary instance of philosophers, who from reasonings purely philosophical ran into as great extravagances of conduct as any Monk or Dervish that ever was. Generally speaking, the errors in religion are dangerous; those in philosophy only ridiculous.
I am aware that these two cases of the strength and weakness of the mind will not comprehend all mankind, and that there are in England, in particular, many honest gentlemen, who being always employed in their domestic affairs or amusing themselves in common recreations have carried their thoughts very little beyond those objects which are every day exposed to their senses. And indeed, of such as these I pretend not to make philosophers. Nor do I expect them either to be associates in these researches or auditors of these discoveries. They do well to keep themselves in their present situation. Instead of refining them into philosophers, I wish we could communicate to our founders of systems a share of this gross earthy mixture as an ingredient, which they commonly stand much in need of, and which would serve to temper those fiery particles of which they are composed. While a warm imagination is allowed in philosophy, and hypotheses embraced merely for being specious and agreeable, we can never have any steady principles, nor any sentiments, which will suit common practice and experience. But were these hypotheses once removed we might hope to establish a system or set of opinions, which if not true (for that, perhaps, is too much to be hoped for) might at least be satisfactory to the human mind, and might stand the test of the most critical examination. Nor should we despair of attaining this end because  of the many chimerical systems which have successively arisen and decayed away among men, would we consider the shortness of that period wherein these questions have been the subjects of enquiry and reasoning. Two thousand years with such long interruptions and under such mighty discouragements are a small space of time to give any tolerable perfection to the sciences. Perhaps we are still in too early an age of the world to discover any principles which will bear the examination of the latest posterity. For my part, my only hope is that I may contribute a little to the advancement of knowledge by giving in some particulars a different turn to the speculations of philosophers, and pointing out to them more distinctly those subjects where alone they can expect assurance and conviction. Human Nature is the only science of man; and yet has been hitherto the most neglected. It will be sufficient for me if I can bring it a little more into fashion. The hope of this serves to restore my temper from that spleen, and invigorate it from that indolence which sometimes prevail upon me. If the reader finds himself in the same easy disposition, let him follow me in my future speculations. If not, let him follow his inclination, and wait the returns of application and good humour. The conduct of a man who studies philosophy in this careless manner is more truly sceptical than that of one, who feeling in himself an inclination to it, is yet so overwhelmed with doubts and scruples, as totally to reject it. A true sceptic will be diffident of his philosophical doubts as well as of his philosophical conviction; and he will never refuse any innocent satisfaction which offers itself upon account of either of them.
Nor is it proper we should in general indulge our inclination only in the most elaborate philosophical researches, notwithstanding our sceptical principles, but also that we should yield to that propensity which inclines us to be positive and certain in particular points, according to the light in which we survey them in any particular instant.  It is easier to forbear all examination and enquiry than to check in ourselves so natural a propensity, and guard against that assurance which always arises from an exact and full survey of an object. On such an occasion we are apt not only to forget our scepticism, but even our modesty too; and make use of such terms as these— it is evident, it is certain, it is undeniable— which a due deference to the public ought, perhaps, to prevent. I may have fallen into this fault after the example of others; but I here enter a caveat against any Objections, which may be offered on that head; and declare that such expressions were extorted from me by the present view of the object, and imply no dogmatical spirit, nor conceited idea of my own judgment, which are sentiments that I am sensible can become nobody, and a sceptic still less than any other.