按键盘上方向键 ← 或 → 可快速上下翻页,按键盘上的 Enter 键可回到本书目录页,按键盘上方向键 ↑ 可回到本页顶部!
————未阅读完?加入书签已便下次继续阅读!
What are those inductions and deductions; and how have you got at
this hypothesis? You have observed in the first place; that the
window is open; but by a train of reasoning involving many
inductions and deductions; you have probably arrived long before at
the general lawand a very good one it isthat windows do not
open of themselves; and you therefore conclude that something has
opened the window。 A second general law that you have arrived at
in the same way is; that tea…pots and spoons do not go out of a
window spontaneously; and you are satisfied that; as they are not
now where you left them; they have been removed。 In the third
place; you look at the marks on the windowsill; and the shoe…marks
outside; and you say that in all previous experience the former
kind of mark has never been produced by anything else but the hand
of a human being; and the same experience shows that no other
animal but man at present wears shoes with hob…nails in them such
as would produce the marks in the gravel。 I do not know; even if
we could discover any of those 〃missing links〃 that are talked
about; that they would help us to any other conclusion! At any
rate the law which states our present experience is strong enough
for my present purpose。 You next reach the conclusion that; as
these kind '89' of marks have not been left by any other animal than
man; or are liable to be formed in any other way than a man's hand
and shoe; the marks in question have been formed by a man in that
way。 You have; further; a general law; founded on observation and
experience; and that; too; is; I am sorry to say; a very universal
and unimpeachable one;that some men are thieves; and you assume
at once from all these premissesand that is what constitutes your
hypothesisthat the man who made the marks outside and on the
window…sill; opened the window; got into the room; and stole your
tea…pot and spoons。 You have now arrived at a vera causa;you
have assumed a cause which; it is plain; is competent to produce
all the phenomena you have observed。 You can explain all these
phenomena only by the hypothesis of a thief。 But that is a
hypothetical conclusion; of the justice of which you have no
absolute proof at all; it is only rendered highly probable by a
series of inductive and deductive reasonings。
I suppose your first action; assuming that you are a man of
ordinary common sense; and that you have established this
hypothesis to your own satisfaction; will very likely be to go off
for the police; and set them on the track of the burglar; with the
view to the recovery of your property。 But just as you are
starting with this object; some person comes in; and on learning
what you are about; says; 〃My good friend; you are going on a great
deal too fast。 How do you know that the man who really made the
marks took the spoons? It might have been a monkey that took them;
and the man may have merely looked in afterwards。〃 You would
probably reply; 〃Well; that is all very well; but you see it is
contrary to all experience of the way tea…pots and spoons are
abstracted; so that; at any rate; your hypothesis is less probable
than mine。〃 While you are talking the thing over in this way;
another friend arrives; one of the good kind of people that I was
talking of a little while ago。 And he might say; 〃Oh; my dear sir;
you are certainly going on a great deal too fast。 You are most
presumptuous。 You admit that all these occurrences took place when
you were fast asleep; at a time when you could not possibly have
known anything about what was taking place。 How do you know that
the laws of Nature are not suspended during the night? It may be
that there has been some kind of supernatural interference in this
case。〃 In point of fact; he declares that your hypothesis is one
of which you cannot at all demonstrate the truth; and that you are
by no means sure that the laws of Nature are the same when you are
asleep as when you are awake。
Well; now; you cannot at the moment answer that kind of reasoning。
You feel that your worthy friend has you somewhat at a
disadvantage。 You will feel perfectly convinced in your own mind;
however; that you are quite right; and you say to him; 〃My good
friend; I can only be guided by the natural probabilities of the
case; and if you will be kind enough to stand aside and permit me
to pass; I will go and fetch the police。〃 Well; we will suppose
that your journey is successful; and that by good luck you meet
with a policeman; that eventually the burglar is found with your
property on his person; and the marks correspond to his hand and to
his boots。 Probably any jury would consider those facts a very
good experimental verification of your hypothesis; touching the
cause of the abnormal phenomena observed in your parlor; and would
act accordingly。
Now; in this supposititious case; I have taken phenomena of a very
common kind; in order that you might see what are the different
steps in an ordinary process of reasoning; if you will only take
the trouble to analyse it carefully。 All the operations I have
described; you will see; are involved in the mind of any man of
sense in leading him to a conclusion as to the course he should
take in order to make good a robbery and punish the offender。 I
say that you are led; in that case; to your conclusion by exactly
the same train of reasoning as that which a man of science pursues
when he is endeavouring to discover the origin and laws of the most
occult phenomena。 The process is; and always must be; the same;
and precisely the same mode of reasoning was employed by Newton '90'
and Laplace '91' in their endeavours to discover and define the causes
of the movements of the heavenly bodies; as you; with your own common
sense; would employ to detect a burglar。 The only difference is;
that the nature of the inquiry being more abstruse; every step has
to be most carefully watched; so that there may not be a single
crack or flaw in your hypothesis。 A flaw or crack in many of the
hypotheses of daily life may be of little or no moment as affecting
the general correctness of the conclusions at which we may arrive;
but; in a scientific inquiry; a fallacy; great or small; is always
of importance; and is sure to be in the long run constantly
productive of mischievous if not fatal results。
Do not allow yourselves to be misled by the common notion that an
hypothesis is untrustworthy simply because it is an hypothesis。 It
is often urged; in respect to some scientific conclusion; that;
after all; it is only an hypothesis。 But what more have we to
guide us in nine…tenths of the most important affairs of daily life
than hypotheses; and often very ill…based ones? So that in
science; where the evidence of an hypothesis is subjected to the
most rigid examination; we may rightly pursue the same course。 You
may have hypotheses; and hypotheses。 A man may say; if he likes;
that the mo