Thomas Reid.

The works of Thomas Reid, D.D.; now fully collected, with selections from his umpublished letters online

. (page 99 of 114)
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pute among men who are not blinded by
prejudice or partiality; for the rules of
reasoning by which inferences may be drawn
from premises have been for two thousand
years fixed with great unanimity . No man
pretends to dispute tile rules of reasoning

laid down by Aristotle and repeated by
every writer in dialectics. [504]

And we may observe by the way, that
the reason why logicians have been so una-
nimous in determining the rules of reason-
ing, from Aristotle down to this day, seems
to be, that they were by that great genius
raised, in a scientific manner, from a few
definitions and axioms. It may farther be
observed, that, when men differ about a
deduction, whether it follows from certain
premises, this I think is always owing to
their differing about some first principle.
I shall explain this by an example.

Suppose that, from a thing having begun
to exist, one man infers that it must have
had a cause ; another man does not admit
the inference. Here it is evident, that the
first takes it for a self-evident principle, that
everything which begins to exist must liave
a cause. The other does not allow this to
be self-evident. Let them settle this point,
and the dispute will be at an end.

Thus, I think, it appears, that, in matters
of science, if the terms be properly explained,
the first principles upon which the reason-
ing is grounded be laid down and exposed
to examination, and the conclusions re-
gularly deduced from them, it might be
expected that men of candour and capacity,
who love truth, and have patience to ex-
amine things coolly, might come to unani-
mity with regard to the force of the deduc-
tions, and that their differences might be
reduced to those they may have about first

4. A fourth proposition is, That Nature
hath not left us destitute of means whereby
the candid and honest part of mankind may
be brought to unanimity when they happen
to differ about first principles. [565]

When men differ about things that are
taken to be first principles or self-evident
truths, reasoning seems to be at an end.
Each party appeals to common sense. When
one man's common sense gives one deter-
mination, another man's a contrary deter-
mination, there seems to be no remedy but
to leave every man to enjoy his own opinion.
This is a common observation, and, I be-
lieve, a just one, if it be rightly understood.

It is in vain to reason with a man who
denies the first principles on which the rea-
soning is grounded. Thus, it would be in
vain to attempt the proof of a proposition
in Euclid to a man who denies the axioms.
Indeed, we ought never to reason with men
who deny first principles from obstinacy
and unwillingness to yield to reason.

But is it not possible, that men who really
love truth, and are open to conviction, may
differ about first principles ?

I think it is possible, and that it cannot,
without great want of charity, bo denied to
be possible-




When this happens, every man who be-
lieves that there is a real distinction between
truth and error, and that the faculties which
God has given us are not in their nature
fallacious, must be convinced that there is
ii defect or a perversion of judgment on
the one side or the other.

A man of candour and humility will, in
such a case, very naturally suspect his own
judgment, so far as to be desirous to enter
into a serious examination, even of what
he has long held as a first principle. He
will think it not impossible, that, although
his heart be upright, his judgment may have
been perverted, by education, by authority,
by party zeal, or by some other of the com-
mon causes of error, from the influence of
which neither parts nor integrity exempt
the human understanding. [5u'G]

In such a state of mind, so amiable, and
so becoming every good man, has Nature
loft him destitute of any rational means by
which lie may be enabled, either to correct
his judgment if it be wrong, or to confirm
it if it be right ?

I hope it is not so. I hope that, by the
means which nature has furnished, con-
troversies about first principles may be
brought to an issue, and that the real lovers
of truth may come to unanimity with regard \
to them.

It is true that, in other controversies,
the process by which the truth of a propo-
sition is discovered, or its falsehood detected,
is, by shewing its necessary connection with
first principles, or its repugnancy to them
It is true, likewise, that, when the contro-
versy is, whether a preposition be itself a
first principle, this process cannot be ap-
plied. The truth, therefore, in controversies
of this kind, labours under a peculiar dis-
advantage. But it has advantantages of
another kind to compensate this.

1. For, in thejirst place, in such con-
troversies, every man is a competent judge;
and therefore it is difficult to impose upon

To judge of first principles, requires no
more than a sound mind free from preju-
dice, and a distinct conception of the question.
The learned and the unlearned, the phi-
losopher and the day-labourer, are upon a
level, and will pass the same judgment,
when they are not misled by some bias, or
taught to renounce their understanding
from some mistaken religious principle.

Tn matters beyond the reach of common
understanding, the many are led by the
few, and willingly yield to their authority.
.But, in matters of common sense, the few
most yield to the many, when local and
trinporary prejudices are removed. No
man is now moved by the subtle arguments
of Zeno against motion, though, perhaps, he
kno.\s not how to answer them. [507 !

The ancient sceptical system furnishes a
remarkable instance of this truth. That
system, of which Pyrrho'was reputed the
father, was carried down, through a succes-
sion of ages, by very able and acute philo-
sophers, who taught men to believe nothing
at all, and esteemed it the highest pitch of
human wisdom to withhold assent from
every proposition whatsoever. It was sup-
ported with very great subtil ty and learning,
as we see from the writings of Sextus Eui-
piricus, the only author of that sect whose
writings have come down to our age. The
assault of the sceptics against all science
seems to have been managed with more art
and address than the defence of the dog-

Yet, as this system was an insult upon the
common sense of mankind, it died away of
itself; and it would be in vain to attempt
to revive it. The modern scepticism is very
different from the ancient, otherwise it would
not have been allowed a hearing ; and, when
it has lost the grace of novelty, it will die
away also, though it should never be refuted.

The modern scepticism, I mean that of
Mr Hume, is built upon principles which
were very generally maintained by philo-
sophers, though they did not see that they
led to scepticism. Mr Hume, by tracing,
with great acuteness and. ingenuity, the con-
sequences of principles commonly received,
has shewn that they overturn all knowledge,
and at last overturn themselves, and leave
the mind in perfect suspense.

2. Secondly, We may observe that opin-
ions which contradict first principles, are
distinguished, from other errors, by this : —
That they are not only false but absurd ;
and, to discountenance absurdity, Nature
hath given us a particular emotion — to wit,
that of ridicule— which seems intended for
this very purpose of putting out of counte-
nance what is absurd, either in opinion or
practice. [568]

This weapon, when properly applied, cuts
with as keen an edge as argument. Nature
hath furnished us with the first to expose
absurdity ; as with the last to refute error.
Both are well fitted for their several offices,
and are equally friendly to truth when pro-
perly used.

Both may be abused to serve the cause
of error ; but the same degree of judgment
which serves to detect the abuse of argu-
ment in false reasoning, serves to detect the
abuse of ridicule when it is wrong directed.

Some have, from nature, a happier talent
for ridicule than others ; and the same
thing holds with regard to the talent of
reasoning. Indeed, I conceive there is
hardly any absurdity, which, when touched
with the pencil of a Lucian, a, Swift, or a
Voltaire, would not be put out of counte-
nance, when there is not some religious




panic, or very powerful prejudice, to blind
the understanding.

But it must lie acknowledged that the
emotion of ridicule, even when most natu-
ral, may be stifled by an emotion of a con-
trary nature, and cannot operate till that
is removed.

Thus, if the notion of sanctity is annexed
to an object, it is no longer a laughable
matter ; and this visor must be pulled off
before it appears ridiculous. Hence we
see, that notions which appear most ridicu-
lous to all who consider them coolly and in-
differently, have no such appearance to
those who never thought of them but under
the impression of religious awe and dread.

Even where religion is not concerned,
the novelty of an opinion to those who are
too fond of novelties ; the gravity and
solemnity with which it is introduced ; the
opinion we have entertained of the author ;
its apparent connection with principles
already embraced, or subserviency to in-
terests which we have at heart ; and, above
all, its being fixed in our minds at that time
of life when we receive implicitly what we
are taught — may cover its absurdity, and
fascinate the understanding for a time.

But, if ever we are able to view it naked,
and stripped of those adventitious circum-
stances from which it borrowed its import-
ance and authority, the natural emotion of
ridicule will exert its force. An absurdity
can be entertained by men of sense no longer
than it wears a mask. When any man is
found who has the skill or the boldness to
pull off the mask, it can no longer bear the
light ; it slinks into dark corners for a while,
and then is no more heard of, but as an ob-
ject of ridicule.

Thus I conceive, that first principles,
which are really the dictates of common
sense, and directly opposed to absurdities
in opinion, will always, from the constitu-
tion of human nature, support themselves,
and gain rather than lose ground among

3. Thirdly, It may be observed, that, al-
though it is contrary to the nature of first
principles to admit of direct or apodictical
proof; yet there are certain ways of reason-
ing even about them, by which those that
are just and solid may be confirmed, and
those that are false may be detected. It
may here be proper to mention some of the
topics from which we may reason in matters
of this kind.

First, It is a good argument ad hommem,
if it can be shewn that a first principle
which a man rejects, stands upon the same
footing with others which he admits : for,
when this is the case, he must be guilty of
an inconsistency who holds the one and
rejects the other.
[ 569-571"]

Thus the faculties of consciousness, of
memory, of external sense, and of reason,
are all equally the gifts of nature. No good
reason can be assigned for receiving the
testimony of one of them, which is not of
equal force with regard to the others. The
greatest sceptics admit the testimony of
consciousness, and allow that what it testi-
fies is to be held as a first principle. If,
therefore, they reject the immediate testi
mony of sense or of memory, they are
guilty of an inconsistency. [570]

Secondly, A first principle may admit of
a proof ad absurdum.

In this kind of proof, which is very com-
mon in mathematics, we suppose the con-
tradictory proposition to be true. We trace
the consequences of that supposition in a
train of reasoning ; and, if we find any of
its necessary consequences to be manifestly
absurd, we conclude the supposition from
which it followed to be false ; and, there»
fore its contradictory to be true.

There is hardly any proposition, especially
of those that may claim the character of
first principles, that stands alone and un-
connected. It draws many others along
with it in a chain that cannot be broken.
He that takes it up must bear the burden
of all its consequences ; and, if that is too
heavy for him to bear, he must not pretend
to take it up.

Thirdly, I conceive that the consent of
ages and nations, of the learned and un-
learned, ought to have great authority with
regard to first principles, where every man
is a competent judge.

Our ordinary conduct in life is built upon
first principles, as well as our speculations
in philosophy ; and every motive to action
supposes some belief. When we find a
general agreement among men, in principles
that concern human life, this must have
great authority with every sober mind that
loves truth.

It is pleasant to observe the fruitless
pains which Bishop Berkeley takes to shew
that his system of the non-existence of a
material world did not contradict the senti-
ments of the vulgar, but those only of the

With good reason he dreaded more to
oppose the authority of vulgar opinion in a
matter of this kind, than all the schools of
philosophers. [571]

Here, perhaps, it will be said. What has
authority to do in matters of opinion ? Is
truth to be determined by most votes ? Or
is authority to be again raised out of its
grave to tyrannise over mankind ?

I am aware that, in this age, an advo-
cate for authority has a very unfavourable
plea ; but I wish to give no more tu author-
ity than is its due.

Most justly do we honour the names of



those benefactors to mankind who have con-
tributed more or less to break the yoke of
that authority which deprives men of the
natural, the unalienable right of judging
for themselves ; but, while we indulge a
just animosity against this authority, and
against all who would subject us to its
tyranny, let us remember how common the
folly is, of going from one faulty extreme
into the opposite.

Authority, though a very tyrannical mis-
tress to private judgment, may yet, on some
occasions, be a useful handmaid. This is
all she is entitled to, and this is all I plead
in her behalf.

The justice of this plea will appear by
putting a case in a science, in which, of all
sciences, authority is acknowledged to have
least weight.

Suppose a mathematician has made a
discovery in that science which he thinks
important; that he has put his demonstra-
tion in just order ; and, after examining it
with an attentive eye, has found no flaw in
it, I would ask, Will there not be still in
his breast some diffidence, some jealousy,
lest the ardour of invention may have made
him overlook some false step ? This must
bo granted. [572]

He commits his demonstration to the ex-
amination of a mathematical friend, whom
he esteems a competent judge, and waits
with impatience the issue of his judgment.
Here I would ask again, Whether the verdict
of his friend, according as it is favourable
or unfavourable, will not greatly increase or
d iniiuishh is confidence in hisown judgment?
Most certainly it will, and it ought.

If the judgment of his friend agree with
his own, especially if it be confirmed by two
or three able judges, he rests secure of his
discovery without farther examination ; but,
if it be unfavourable, he is brought back
into a kind of suspense, until the part that
is suspected undergoes a new and a more
rigorous examination.

I hope what is supposed in this case is
agreeable to nature, and to the experience
of candid and modest men on such occa-
sions ; yet here we see a man's judgment,
even in a mathematical demonstration, con-
scious of some feebleness in itself, seeking
the aid of authority to support it, greatly
strengthened by that authority, and hardly
able to stand erect against it, without some
new aid.

Society in judgment, of those who are
esteemed fair and competent judges, has
effects very similar to those of civil society :
it gives strength and courage to every indi-
vidual ; it removes that timidity which is
as naturally the companion of solitary judg-
ment, as of a solitary man in the state of

Let us judge for ourselves, therefore ; but

let us not disdain to take that aid from the
authority of other competent judges, which
a mathematician thinks it necessary to take
in that science which, of all sciences, has
least to do with authority.

In a matter of common sense, every man
is no less a competent judge than a mathe-
matician is in a mathematical demonstra-
tion ; and there must be a great presump-
tion that the judgment of mankind, in such
a matter, is the natural issue of those facul-
ties which God hath given them. Such a
judgment can be erroneous only when there
is some cause of the error, as general as the
error is. When this can be shewn to be the
case, I acknowledge it ought to have its due
weight. But, to suppose a general devia-
tion from truth among mankind in things
self-evident, of which no cause can be
assigned, is highly unreasonable. [573]

perhaps it may be thought impossible
to collect the general opinion of men upon
any point whatsoever; and, therefore, that
this authority can serve us iu no stead in
examining first principles. But I appre-
hend that, in many cases, this is neither
impossible nor difficult.

Who can doubt whether men have uni-
versally believed the existence of a mate-
rial world ? Who can doubt whether men
have universally believed that every change
that happens in nature must have a cause ?
Who can doubt whether men have uni-
versally believed, that there is a right and
a wrong in human conduct; some things
that merit blame, and others that are en-
titled to approbation ?

The universality of these opinions, and
of many such that might be named, is suf-
ficiently evident, from the whole tenor of
human conduct, as far as our acquaintance
reaches, and from the history of all ages
and nations of which we have any records.

There are other opinions that appear to
be universal, from what is common in the
structure of all languages-
Language is the express image and pic-
ture of human thoughts ; and from the
picture we may draw some certain conclu-
sions concerning the original.

We find in all languages the same parts
of speech ; we find nouns, substantive and
adjective; verbs, active and passive, in
their various tenses, numbers, and moods.
Some rules of syntax are the same in all

Now, what is common in the structure
of languages, indicates an uniformity of
opinion in those things upon which that
structure is grounded. [574]

The distinction between substances, and
the qualities belonging to them ; between
thought and the being that thinks ; be-
tween thought and the objects of thought ;
is to be found in the structure of all lan-



guages. And, therefore, systems of philo-
sophy, which abolish those distinctions, wage
war with the common sense of mankind.

We are apt to imagine that those who
formed languages were no metaphysicians ;
but the first principles of all sciences are
the dictates of common sense, and lie open
to all men ; and every man who has con-
sidered the structure of language in a phi-
losophical light, will find infallible proofs that
those who have framed it, and those who
use it with understanding have the power
of making accurate distinctions, and of form-
ing general conceptions, as well as philoso-
phers. Nature has given those powers to
all men, and they can use them when occa-
sions require it, but they leave it to the
philosophers to give names to them, and to
descant upon their nature. In like manner,
nature has given eyes to all men, and they
can make good use of them ; but the struc-
ture of the eye, and the theory of vision, is
the business of philosophers.

Fourthly, Opinions that appear so early
in the minds of men that they cannot be
the effect of education or of false reason-
ing, have a good claim to be considered as
fi st principles. Thus, the belief we have,
that the persons about us are living and in-
telligent beings, is a belief for which, per-
haps, we can give some reason, when we
are able to reason ; but we had this belief
before we could reason, and before we could
learn it by instruction. It seems, there-
fore, to be an immediate effect of our con-
it. tution.

The last topic I shall mention is, when
an opinion is so necessary in the conduct of
life, that, without the belief of it, a man
must be led into a thousand absurdities in
practice, such an opinion, when we can
give no other reason for it, may safely be
taken for a first principle. [575]

Thus I have endeavoured to shew, that,
although first principles are not capable of
direct proof, yet differences, that may hap-
pen with regard to them among men of
candour, are not without remedy ; that
Nature has not left us destitute of means
by which we may discover errors of this
kind ; and that there are ways of reason-
ing, with regard to first principles, by which
those that are truly such may be distin-
guished from vulgar errors or prejudices.



" Surelv," says Bishop Berkeley, " it is
a work well deserving our pains to make
a strict inquiry concerning the first princi-
ples of knowledge ; to sift and examine
[575, 576]

them on all sides." What was said in the
last chapter is intended both to shew the
importance of this inquiry, and to make it
more easy.

But, in order that such an inquiry may be
actually made, it is necessary that the first
principles of knowledge be distinguished
from other truths, and presented to view,
that they may be sifted and examined on
all sides. In order to this end, I shall
attempt a detail of those I take to be such,
and of the reasons why I think them entitled
to that character. [67b']

If the enumeration should appear to some
redundant, to others deficient, and to others
both— if things which I conceive to be first
principles, should to others appear to be
vulgar errors, or to be truths which derive
their evidence from other truths, and there-
fore not first principles - in these things
every man must judge for himself. I shall
rejoice to see an enumeration more perfect
in any or in all of those respects ; being
persuaded that the agreement of men of
judgment' and candour in first principles
would be of no less consequence to the ad-
vancement of knowledge in general, than
the agreement of mathematicians in the
axioms of geometry has been to the ad-
vancement of that science.

The truths that fall within the compass
of human knowledge, whether they be self-
evident, or deduced from those that are
self-evident, may be reduced to two classes.
They are either necessary and immutable
truths, whose contrary is impossible ; or
they are contingent and mutable, depend-
ing upon some effect of will and power,
which had a beginning, and may have an

That a cone is the third part of a cylin-
der of the same base and the same altitude,
is a necessary truth. It depends not upon
the will and power of any being. It is im-
mutably true, and the contrary impossible.
That the sun is the centre about which the
earth, and the other planets of our system,
perform their revolutions, is a, truth ; but
it is nut a necessary truth. It depends
upon the power and will of that Being who
made the sun and all the planets, and who
gave them those motions that seemed best
to him.

If all truths were necessary truths, there
would be no occasion for different tenses in
the verbs by which they are expressed.
What is true in the present time, w< uld Le
true in the past and future ; and there
would bo no change or variation of an; thing
in nature.

We use the present tense in expressing
necessary truths; but it is only because
there is no flexion of the verb which in-
cludes all times. When I say that, three
is the half of six, I use the present tense




only ; but I mean to express not only what
now is, but what always was, and always will
be ; and so every proposition is to be under-
stood by which we mean to express a neces-
sary truth. Contingent truths are of an-
other nature. As they are mutable, they
may be true at one time, and not at an-
other ; and, therefore, the expression of
then! must include some point or period of
time. [577 J

If language had been a contrivance of

Online LibraryThomas ReidThe works of Thomas Reid, D.D.; now fully collected, with selections from his umpublished letters → online text (page 99 of 114)