| David Hume An
Enquiry Concerning Human Understanding
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Section IX: Of the Reason
ALL our reasonings concerning matter of
fact are founded on a species of Analogy, which leads us to expect
from any cause the same events, which we have observed to result
from similar causes. Where the causes are entirely similar, the
analogy is perfect, and the inference, drawn from it, is regarded as
certain and conclusive: nor does any man ever entertain a doubt,
where he sees a piece of iron, that it will have weight and cohesion
of parts; as in all other instances, which have ever fallen under
hit observation. But where the objects have not so exact a
similarity, the analogy is less perfect, and the inference is less
conclusive; though still it has some force, in proportion to the
degree of similarity and resemblance. The anatomical observations,
formed upon one animal, are, by this species of reasoning, extended
to all animals; and it is certain, that when the circulation of the
blood, for instance, is clearly proved to have place in one
creature, as a frog, or fish, it forms a strong presumption, that
the same principle has place in all. These analogical observations
may be carried farther, even to this science, of which we are now
treating; and any theory, by which we explain the operations of the
understanding, or the origin and connection of the passions in man,
will acquire additional authority, if we find, that the same theory
is requisite to explain the same phenomena in all other animals. We
shall make trial of this, with regard to the hypothesis, by which we
have, in the foregoing discourse, endeavored to account for all
experimental reasonings: and it is hoped, that this new point of
view will serve to confirm all our former observations.
First, It seems evident, that animals
as well as men learn many things from experience, and infer, that
the same events will always follow from the same causes. By this
principle they become acquainted with the more obvious properties of
external objects, and gradually, from their birth, treasure up a
knowledge of the nature of fire, water, earth, stones, heights,
depths, &c., and of the effects which result from their
operation. The ignorance and inexperience of the young are here
plainly distinguishable from the cunning and sagacity of the old,
who have learned, by long observation, to avoid what hurt them, and
to pursue what gave ease or pleasure. A horse, that has been
accustomed to the field, becomes acquainted with the proper height
which he can leap, and will never attempt what exceeds his force and
ability. An old greyhound will trust the more fatiguing part of the
chase to the younger, and will place himself so as to meet the hare
in her doubles; nor are the conjectures, which he forms on this
occasion, founded in any thing but his observation and experience.
This is still more evident from the
effects of discipline and education on animals, who, by the proper
application of rewards and punishments, may be taught any course of
action, and most contrary to their natural instincts and
propensities. Is it not experience, which renders a dog apprehensive
of pain, when you menace him, or lift up the whip to beat him? Is it
not even experience, which makes him answer to his name, and infer,
from such an arbitrary sound, that you mean him rather than any of
his fellows, and intend to call him, when you pronounce it in a
certain manner, and with a certain tone and accent?
In all these cases, we may observe,
that the animal infers some fact beyond what immediately strikes his
senses; and that this inference is altogether founded on past
experience, while the creature expects from the present object the
same consequences, which it has always found in its observation to
result from similar objects.
Secondly, It is impossible, that this
inference of the animal can be founded on any process of argument or
reasoning, by which he concludes, that like events must follow like
objects, and that the course of nature will always be regular in its
operations. For if there be in reality any arguments of this nature,
they surely lie too abstruse for the observation of such imperfect
understandings; since it may well employ the utmost care and
attention of a philosophic genius to discover and observe them.
Animals, therefore are not guided in these inferences by reasoning:
neither are children; neither are the generality of mankind, in
their ordinary actions and conclusions: neither are philosophers
themselves, who, in all the active parts of life, are, in the main
the same with the vulgar, and are governed by of the same maxims.
Nature must have provided some other principle, more ready, and more
general use and application; nor can an operation of such immense
consequence in life, as that of inferring effects from causes, be
trusted to the uncertain process of reasoning and argumentation.
Were this doubtful with regard to men, it seems to admit of no
question with regard to the brute creation; and the conclusion being
once firmly established in the one, we have a strong presumption,
from all the rules of analogy, that it ought to be universally
admitted, without any exception or reserve. It is custom alone,
which engages animals, from every object, that strikes their senses,
to infer its usual attendant, and carries their imagination, from
the appearance of the one, to conceive the other, in that particular
manner, which we denominate belief. No other explication can be
given of this operation, in all the higher, as well as lower classes
of sensitive beings, which fall under our notice and observation.
But though animals learn many parts of
their knowledge from observation, there are also many parts of it,
which they derive from the original hand of nature; which much
exceed the share of capacity they possess on ordinary occasions; and
in which they improve, little or nothing, by the longest practice
and experience. These we denominate Instincts, and are so apt to
admire as something very extraordinary, and inexplicable by all the
disquisitions of human understanding. But our wonder will, perhaps,
cease or diminish, when we consider, that the experimental reasoning
itself, which we possess in common with beasts, and on which the
whole conduct of life depends, is nothing but a species of instinct
or mechanical power, that acts in us unknown to ourselves; and in
its chief operations, is not directed by any such relations or
comparisons of ideas, as are the proper objects of our intellectual
faculties. Though the instinct be different, yet still it is an
instinct, which teaches a man to avoid the fire; as much as that,
which teaches a bird, with such exactness, the art of incubation,
and the whole economy and order of its nursery.
Footnote 1. Since all reasoning concerning
facts or causes is derived merely from custom, it may be asked how it
happens, that men so much surpass animals in reasoning, and one man so
much surpasses another? Has not the same custom the same influence on
We shall here endeavor briefly to explain the great difference in
human understandings: After which the reason of the difference between
men and animals will easily be comprehended.
1. When we have lived any time, and have been accustomed to the
uniformity of nature, we acquire a general habit, by which we always
transfer the known to the unknown, and conceive the latter to resemble
the former. By means of this general habitual principle, we regard
even one experiment as the foundation of reasoning, and expect a
similar event with some degree of certainty, where the experiment has
been made accurately and free from all foreign circumstances. It is
therefore considered as a matter of great importance to observe the
consequences of things; and as one man may very much surpass another
in attention and memory and observation, this will make a very great
difference in their reasoning.
2. Where there is a complication of causes to produce any effect, one
mind may be much larger than another, and better able to comprehend
the whole system of objects, and to infer justly their consequences.
3. One man is able to carry on a chain of consequences to a greater
length than another.
4. Few men can think long without running into a confusion of ideas,
and mistaking one for another; and there are various degrees of this
5. The circumstance, on which the effect depends, is frequently
involved in other circumstances, which are foreign and extrinsic. The
separation of it often requires great attention, accuracy, and
6. The forming of general maxims from particular observation is a very
nice operation; and nothing is more usual, from haste or a narrowness
of mind, which sees not on all sides, than to commit mistakes in this
7. When we reason from analogies, the man, who has the greater
experience or the greater promptitude of suggesting analogies, will be
the better reasoner.
8. Biases from prejudice, education, passion, party, &c. hang more
upon one mind than another.
9. After we have acquired a confidence in human testimony, books and
conversation enlarge much more the sphere of one manís experience
and thought than those of another.
It would be easy to discover many other circumstances that make a
difference in the understandings of men.