Inference da capo

[Robert Robbins]

On Tue, 1 Aug 1995, Richard Zander wrote:

> The Hume quote must be some kind of overenthusiasm on someone's part.
> Inference works because nature is *locally* uniform, not globally so.

Zander's assertion misses the point that philosophers have always found it
easier to doubt induction that to justify it, despite the demonstrated
success of empiricists.  Hume expresses no doubt that empiricism works, he
just doubts that a formal justification for its working can be provided.

Thus, no overly enthusiastic paraphrasing was involved.  However, since
we are all empiricists on this list, I offer Hume himself:

                     ... But you must confess that [induction] is not
      intuitive; neither is it demonstrative: Of what nature is it,
      then? To say it is experimental, is begging the question. For all
      inferences from experience suppose, as their foundation, that the
      future will resemble the past, and that similar powers will be
      conjoined with similar sensible qualities. If there be any
      suspicion that the course of nature may change, and that the past
      may be no rule for the future, all experience becomes useless, and
      can give rise to no inference or conclusion. It is impossible,
      therefore, that any arguments from experience can prove this
      resemblance of the past to the future; since all these arguments
      are founded on the supposition of that resemblance.



The larger section, providing context, from which this was extracted,
follows...


        AN ENQUIRY CONCERNING HUMAN UNDERSTANDING by DAVID HUME

   SECTION IV: SCEPTICAL DOUBTS CONCERNING THE OPERATIONS OF THE
               UNDERSTANDING

   PART II

      BUT we have not yet attained any tolerable satisfaction with
      regard to the question first proposed. Each solution still gives
      rise to a new question as difficult as the foregoing, and leads us
      on to farther enquiries. When it is asked, What is the nature of
      all our reasonings concerning matter of fact? the proper answer
      seems to be, that they are founded on the relation of cause and
      effect. When again it is asked, What is the foundation of all our
      reasonings and conclusions concerning that relation? it may be
      replied in one word, Experience. But if we still carry on our
      sifting humour, and ask, What is the foundation of all conclusions
      from experience? this implies a new question, which may be of more
      difficult solution and explication. Philosophers, that give
      themselves airs of superior wisdom and sufficiency, have a hard
      task when they encounter persons of inquisitive dispositions, who
      push them from every corner to which they retreat, and who are
      sure at last to bring them to some dangerous dilemma. The best
      expedient to prevent this confusion, is to be modest in our
      pretensions; and even to discover the difficulty ourselves before
      it is objected to us. By this means, we may make a kind of merit
      of our very ignorance.

      I shall content myself, in this section, with an easy task, and
      shall pretend only to give a negative answer to the question here
      proposed. I say then, that, even after we have experience of the
      operations of cause and effect, our conclusions from that
      experience are not founded on reasoning, or any process of the
      understanding. This answer we must endeavour both to explain and
      to defend.

      It must certainly be allowed, that nature has kept us at a great
      distance from all her secrets, and has afforded us only the
      knowledge of a few superficial qualities of objects; while she
      conceals from us those powers and principles on which the
      influence of those objects entirely depends. Our senses inform us
      of the colour, weight, and consistence of bread; but neither sense
      nor reason can ever inform us of those qualities which fit it for
      the nourishment and support of a human body. Sight or feeling
      conveys an idea of the actual motion of bodies; but as to that
      wonderful force or power, which would carry on a moving body for
      ever in a continued change of place, and which bodies never lose
      but by communicating it to others; of this we cannot form the most
      distant conception. But notwithstanding this ignorance of natural
      powers [1] and principles, we always presume, when we see like
      sensible qualities, that they have like secret powers, and expect
      that effects, similar to those which we have experienced, will
      follow from them. If a body of like colour and consistence with
      that bread, which we have formerly eat, be presented to us, we
      make no scruple of repeating the experiment, and foresee, with
      certainty, like nourishment and support. Now this is a process of
      the mind or thought, of which I would willingly know the
      foundation. It is allowed on all hands that there is no known
      connexion between the sensible qualities and the secret powers;
      and consequently, that the mind is not led to form such a
      conclusion concerning their constant and regular conjunction, by
      anything which it knows of their nature. As to past Experience, it
      can be allowed to give direct and certain information of those
      precise objects only, and that precise period of time, which fell
      under its cognizance: but why this experience should be extended
      to future times, and to other objects, which for aught we know,
      may be only in appearance similar; this is the main question on
      which I would insist. The bread, which I formerly eat, nourished
      me; that is, a body of such sensible qualities was, at that time,
      endued with such secret powers: but does it follow, that other
      bread must also nourish me at another time, and that like sensible
      qualities must always be attended with like secret powers? The
      consequence seems nowise necessary. At least, it must be
      acknowledged that there is here a consequence drawn by the mind;
      that there is a certain step taken; a process of thought, and an
      inference, which wants to be explained. These two propositions are
      far from being the same. I have found that such an object has
      always been attended with such an effect, and I foresee, that
      other objects, which are, in appearance, similar, will be attended
      with similar effects. I shall allow, if you please, that the one
      proposition may justly be inferred from the other: I know, in
      fact, that it always is inferred. But if you insist that the
      inference is made by a chain of reasoning, I desire you to produce
      that reasoning. The connexion between these propositions is not
      intuitive. There is required a medium, which may enable the mind
      to draw such an inference, if indeed it be drawn by reasoning and
      argument. What that medium is, I must confess, passes my
      comprehension; and it is incumbent on those to produce it, who
      assert that it really exists, and is the origin of all our
      conclusions concerning matter of fact.

      This negative argument must certainly, in process of time, become
      altogether convincing, if many penetrating and able philosophers
      shall turn their enquiries this way and no one be ever able to
      discover any connecting proposition or intermediate step, which
      supports the understanding in this conclusion. But as the question
      is yet new, every reader may not trust so far to his own
      penetration, as to conclude, because an argument escapes his
      enquiry, that therefore it does not really exist. For this reason
      it may be requisite to venture upon a more difficult task; and
      enumerating all the branches of human knowledge, endeavour to show
      that none of them can afford such an argument.

      All reasonings may be divided into two kinds, namely,
      demonstrative reasoning, or that concerning relations of ideas,
      and moral reasoning, or that concerning matter of fact and
      existence. That there are no demonstrative arguments in the case
      seems evident; since it implies no contradiction that the course
      of nature may change, and that an object, seemingly like those
      which we have experienced, may be attended with different or
      contrary effects. May I not clearly and distinctly conceive that a
      body, falling from the clouds, and which, in all other respects,
      resembles snow, has yet the taste of salt or feeling of fire? Is
      there any more intelligible proposition than to affirm, that all
      the trees will flourish in December and January, and decay in May
      and June? Now whatever is intelligible, and can be distinctly
      conceived, implies no contradiction, and can never be proved false
      by any demonstrative argument or abstract reasoning a priori.

      If we be, therefore, engaged by arguments to put trust in past
      experience, and make it the standard of our future judgment, these
      arguments must be probable only, or such as regard matter of fact
      and real existence according to the division above mentioned. But
      that there is no argument of this kind, must appear, if our
      explication of that species of reasoning be admitted as solid and
      satisfactory. We have said that all arguments concerning existence
      are founded on the relation of cause and effect; that our
      knowledge of that relation is derived entirely from experience;
      and that all our experimental conclusions proceed upon the
      supposition that the future will be conformable to the past. To
      endeavour, therefore, the proof of this last supposition by
      probable arguments, or arguments regarding existence, must be
      evidently going in a circle, and taking that for granted, which is
      the very point in question.

      In reality, all arguments from experience are founded on the
      similarity which we discover among natural objects, and by which
      we are induced to expect effects similar to those which we have
      found to follow from such objects. And though none but a fool or
      madman will ever pretend to dispute the authority of experience,
      or to reject that great guide of human life, it may surely be
      allowed a philosopher to have so much curiosity at least as to
      examine the principle of human nature, which gives this mighty
      authority to experience, and makes us draw advantage from that
      similarity which nature has placed among different objects. From
      causes which appear similar we expect similar effects. This is the
      sum of all our experimental conclusions. Now it seems evident
      that, if this conclusion were formed by reason, it would be as
      perfect at first, and upon one instance, as after ever so long a
      course of experience. But the case is far otherwise. Nothing so
      like as eggs; yet no one, on account of this appearing similarity,
      expects the same taste and relish in all of them. It is only after
      a long course of uniform experiments in any kind, that we attain a
      firm reliance and security with regard to a particular event. Now
      where is that process of reasoning which, from one instance, draws
      a conclusion, so different from that which it infers from a
      hundred instances that are nowise different from that single one?
      This question I propose as much for the sake of information, as
      with an intention of raising difficulties. I cannot find, I cannot
      imagine any such reasoning. But I keep my mind still open to
      instruction, if any one will vouchsafe to bestow it on me.

      Should it be said that, from a number of uniform experiments, we
      infer a connexion between the sensible qualities and the secret
      powers; this, I must confess, seems the same difficulty, couched
      in different terms. The question still recurs, on what process of
      argument this inference is founded? Where is the medium, the
      interposing ideas, which join propositions so very wide of each
      other? It is confessed that the colour, consistence, and other
      sensible qualities of bread appear not, of themselves, to have any
      connexion with the secret powers of nourishment and support. For
      otherwise we could infer these secret powers from the first
      appearance of these sensible qualities, without the aid of
      experience; contrary to the sentiment of all philosophers, and
      contrary to plain matter of fact. Here, then, is our natural state
      of ignorance with regard to the powers and influence of all
      objects. How is this remedied by experience? It only shows us a
      number of uniform effects, resulting from certain objects, and
      teaches us that those particular objects, at that particular time,
      were endowed with such powers and forces. When a new object,
      endowed with similar sensible qualities, is produced, we expect
      similar powers and forces, and look for a like effect. From a body
      of like colour and consistence with bread we expect like
      nourishment and support. But this surely is a step or progress of
      the mind, which wants to be explained. When a man says, I have
      found, in all past instances, such sensible qualities conjoined
      with such secret powers: And when he says, Similar sensible
      qualities will always be conjoined with similar secret powers, he
      is not guilty of a tautology, nor are these propositions in any
      respect the same. You say that the one proposition is an inference
      from the other. But you must confess that the inference is not
      intuitive; neither is it demonstrative: Of what nature is it,
      then? To say it is experimental, is begging the question. For all
      inferences from experience suppose, as their foundation, that the
      future will resemble the past, and that similar powers will be
      conjoined with similar sensible qualities. If there be any
      suspicion that the course of nature may change, and that the past
      may be no rule for the future, all experience becomes useless, and
      can give rise to no inference or conclusion. It is impossible,
      therefore, that any arguments from experience can prove this
      resemblance of the past to the future; since all these arguments
      are founded on the supposition of that resemblance. Let the course
      of things be allowed hitherto ever so regular; that alone, without
      some new argument or inference, proves not that, for the future,
      it will continue so. In vain do you pretend to have learned the
      nature of bodies from your past experience. Their secret nature,
      and consequently all their effects and influence, may change,
      without any change in their sensible qualities. This happens
      sometimes, and with regard to some objects: Why may it not happen
      always, and with regard to all objects? What logic, what process
      or argument secures you against this supposition? My practice, you
      say, refutes my doubts. But you mistake the purport of my
      question. As an agent, I am quite satisfied in the point; but as a
      philosopher, who has some share of curiosity, I will not say
      scepticism, I want to learn the foundation of this inference. No
      reading, no enquiry has yet been able to remove my difficulty, or
      give me satisfaction in a matter of such importance. Can I do
      better than propose the difficulty to the public, even though,
      perhaps, I have small hopes of obtaining a solution? We shall at
      least, by this means, be sensible of our ignorance, if we do not
      augment our knowledge.

      I must confess that a man is guilty of unpardonable arrogance who
      concludes, because an argument has escaped his own investigation,
      that therefore it does not really exist. I must also confess that,
      though all the learned, for several ages, should have employed
      themselves in fruitless search upon any subject, it may still,
      perhaps, be rash to conclude positively that the subject must,
      therefore, pass all human comprehension. Even though we examine
      all the sources of our knowledge, and conclude them unfit for such
      a subject, there may still remain a suspicion, that the
      enumeration is not complete, or the examination not accurate. But
      with regard to the present subject, there are some considerations
      which seem to remove all this accusation of arrogance or suspicion
      of mistake.

      It is certain that the most ignorant and stupid peasants--nay
      infants, nay even brute beasts--improve by experience, and learn
      the qualities of natural objects, by observing the effects which
      result from them. When a child has felt the sensation of pain from
      touching the flame of a candle, he will be careful not to put his
      hand near any candle; but will expect a similar effect from a
      cause which is similar in its sensible qualities and appearance.
      If you assert, therefore, that the understanding of the child is
      led into this conclusion by any process of argument or
      ratiocination, I may justly require you to produce that argument;
      nor have you any pretence to refuse so equitable a demand. You
      cannot say that the argument is abstruse, and may possibly escape
      your enquiry; since you confess that it is obvious to the capacity
      of a mere infant. If you hesitate, therefore, a moment, or if,
      after reflection, you produce any intricate or profound argument,
      you, in a manner, give up the question, and confess that it is not
      reasoning which engages us to suppose the past resembling the
      future, and to expect similar effects from causes which are, to
      appearance, similar. This is the proposition which I intended to
      enforce in the present section. If I be right, I pretend not to
      have made any mighty discovery. And if I be wrong, I must
      acknowledge myself to be indeed a very backward scholar; since I
      cannot now discover an argument which, it seems, was perfectly
      familiar to me long before I was out of my cradle.

      [1] The word, Power, is here used in a loose and popular sense.
          The more accurate explication of it would give additional
          evidence to this argument. See Sect. 7.


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        Harvard Classics, Volume 37. 1910. New York: P.F. Collier & Son.
        Prepared by dell at wiretap.spies.com. This was scanned from the
           1910 edition and mechanically checked against a commercial
           copy of the the text from CD-ROM. Differences were corrected
           against the paper edition. The text itself is thus a highly
           accurate rendition. The footnotes were entered manually. This
           text is in the public domain, released August 1993 by the
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