Thomas Reid.

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

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which, from their construction in grammar,
require not only a person or agent, but
likewise an object of the operation. Thus,
the verb know, denotes an operation of
mind. From the general structure of lan-
guage, this verb requires a person — I know,
you know, or he knows ; but it requires no
less a noun in the accusative case, denoting
the thing known ; for he that knows must
know something ; and, to know, without
having any object of knowledge, is an ab-
surdity too gross to admit of reasoning *

7. We ought likewise to take for granted,
as first principles, things wherein we find
an universal agreement, among the learned
and unlearned, in the different nations and
ages of the world. -j- A consent of ages and
nations, of the learned and vulgar, ought,
at least, to have great authority, unless we
can shew some prejudice as universal as
that consent is, which might be the cause
of it. Truth is one, but error is infinite.
There are many truths so obvious to
the human faculties, that it may be ex-
pected that men should universally agree in
them. And this is actually found to be
the case with regard to many truths, against
which we find no dissent, unless perhaps
that of a few sceptical philosophers, who
may justly be suspected, in such cases, to
differ from the rest of mankind, through
pride, obstinacy, or some favourite passion.
Where there is such universal consent
in things not deep nor intricate, but which
lie, as it were, on the surface, there is the
greatest presumption that can be, that it is
the natural result of the human faculties ;
and it must have great authority with every
sober [44] mind that loves truth. Major
eitim pars eo fere deferri solei quo a natura
deducitur. — Cic. de Off. I. 41.

Perhaps it may be thought that it is
impossible to collect the opinions of all men
upon any point whatsoever ; and, there-
fore, that this maxim can be of no use.
But there are many cases wherein it is

» See Note B H.


+ See Note A.— H.

otherwise. Who can doubt, for instance,
whether mankind have, in all ages, believed
the existence of a material world, and that
those things which they see and handle are
real, and not mere illusions and appari-
tions ? Who can doubt whether mankind
have universally believed that everything
that begins to exist, and every change that
happens in nature, must have a cause ?
Who can doubt whether mankind have
been universally persuaded that there is a
right and a wrong in human conduct ? —
some things which, in certain circumstan-
ces, they ought to do, and other things
which they ought not to do ? The univers-
ality of these opinions, and of many such
that might be named, is sufficiently evi-
dent, from the whole tenor of men's con-
duct, as far as our acquaintance reaches,
and from the records of history, in all
ages and nations, that are transmitted to

There are other opinions that appear to
be universal, from what is common in the
structure of all languages, ancient and mo-
dern, polished and barbarous. Language is
the express image and picture of human
thoughts ; and, from the picture, we mayoften
draw very certain conclusions with regard
to the original. We find in all languages the
same parts of speech — nouns substantive
and adjective, verbs active and passive,
varied according to the tenses of past, pre-
sent, and future ; we find adverbs, preposi-
tions, and conjunctions. There are general
rules of syntax common to all languages.
This uniformity in the structure of lan-
guage shews a certain degree of uniformity
in those notions upon which the structure of
language is grounded.

We find, in the structure of all lan-
guages, the distinction of [45] acting and
being acted upon, the distinction of action
and agent, of quality and subject, and many
others of the like kind ; whicl) shews that
these distinctions are founded in the uni-
versal sense of mankind. We shall have
frequent occasion to argue from the sense
of mankind expressed in the structure of
language ; and therefore it was proper
here to take notice of the force of argu-
ments drawn from this topic.

8. I need hardly say that I shall also
take for granted such facts as are attested
to the conviction of all sober and reasonable
men, either by our senses, by memory, or
by human testimony. Although some wri-
ters on this subject have disputed the
authority of the senses, of memory, and of
every human faculty, yet we find that such
persons, in the conduct of life, in pursuing
their ends, or in avoiding dangers, pay the
same regard to the authority of their senses
and other faculties, as the rest of mankind.
By this they give us just ground to doubt of



[essat I.

their candour in their professions of scep-

This, indeed, has always been the fate of
the few that have professed scepticism, that,
when they have done what they can to
discredit their senses, they find themselves,
after all, under a necessity of trusting to
1 hem. Mr Hume has been so candid as to
acknowledge this ; and it is no less true of
those who have not shewn the same can-
dour ; for I never heard that any sceptic
run his head against a post, or stepped into
a kennel, because he did not believe his

Upon the whole, I acknowledge that we
ought to be cautious that we do not adopt
opinions as first principles which are not
entitled to that character. But there is
surely the least danger of men's being im-
posed upon in this way, when such prin-
ciples openly lay claim to the character, and
are thereby fairly exposed to the examina-
tion of those who may dispute their au-
thority. We do not pretend that those
things that are laid down as first principles
may not be examined, and that we ought
not to [46] have our ears open to what
may be pleaded against their being admit-
ted as such. Let us deal with them as an
upright judge does with a witness who has
a fair character. He pays a regard to the
testimony of such a witness while his cha-
racter is unimpeached ; but, if it can be
shewn that he is suborned, or that he is
influenced by malice or partial favour, his
testimony loses all its credit, and is justly



Every branch of human knowledge hath
its proper principles, its proper foundation
and method of reasoning ; and, if we en-
deavour to build it upon any other found-
ation, it will never stand firm and stable.
Thus, the historian builds upon testimony,
and rarely indulges conjecture ; the anti-
quarian mixes conjecture with testimony,
and the former often makes the larger
ingredient ; the mathematician pays not the
least regard either to testimony or conjec-
ture, hut deduces everything, by demon-
strative reasoning, from his definitions and
axioms. Indeed, whatever is built upon
conjecture, is improperly called science ;
for conjecture may beget opinion, but can-
not produce knowledge. Natural philoso-
phy must be built upon the phenomena of
the material system, discovered by observ-
ation and experiment.

When men first began to philosophize —
that is, to carry their thoughts beyond the

objects of sense, and to inquire into the
causes of things, and the secret operations
of nature — it was very natural for them to
indulge conjecture ; nor was it to be ex-
pected that, in many ages, they should dis-
cover the proper and scientific way of pro-
ceeding in philosophical disquisitions. Ac-
cordingly, we find that the most ancient
systems in every branch of philosophy were
nothing but the conjectures of men famous
for their wisdom, whose fame gave author-
ity to their opinions. Thus, in early ages,
[47] wise men conjectured that this earth
is a vast plain, surrounded on all hands
by a boundless ocean ; that, from this ocean ,
the sun, moon, and stars emerge at their
rising, and plunge into it again at their

With regard to the mind, men in their
rudest state are apt to conjecture that the
principle of life in a man is his breath ; be-
cause the most obvious distinction between
a living and a dead man is, that the one
breathes, and the other does not. To this
it is owing that, in ancient languages, the
word which denotes the soul, is that which
properly signifies breath or air.

As men advance in knowledge, their first
conjectures appear silly and childish, and
give place to others, which tally better with
later observations and discoveries. Thus
one system of philosophy succeeds another, .
without any claim to superior merit, but
this — that it is a more ingenious system of
conjectures, and accounts better for com-
mon appearances.

To omit many ancient systems of this
kind, Des Cartes, about the middle of the
last century, dissatisfied with the materia
prima, the substantial forms, and the occult
qualities of the Peripatetics, conjectured
boldly, that the heavenly bodies of our sys-
tem are carried round by a vortex or whirl-
pool of subtile matter, just as straws and
chaff are carried round in a tub of water.
He conjectured, that the soul is seated in a
small gland in the brain, called the pineal
gland ; that there, as in her chamber of
presence, she receives intelligence of every-
thing that affects the senses, by means of a
subtile fluid contained in the nerves, called
the animal spirits ; and that she dispatches
these animal spirits, as her messengers, to
put in motion the several muscles of the
body, as there is occasion.* By such con-

* It is not, however, to be supposed that Des Cartes
allowed the soul to be seated by local presence in any
part of the body ; lor the smalle-t point of body is
still extei ded, and mind is abso'utely simple and in-
capable of occupying'place. The | ineal gland, in the
Cartesian doctrine, is only analogically called the scat
of the soul, inasmuch as this is viewed as the cen-
tral point of the corporeal organism ; but while
through this point the mind and body are mutually,
connected, that connection is not one of a mere
physical dependence, as they do not operate on each
bv direct and natural causation.— H.

[Ki, 17]




jectures as these, Dcs Cartes could account
for every phenomenon in nature, in such a
plausible manner as gave satisfaction to a
great part of the learned world for more
than half a century. [48]

Such conjectures in philosophical matters
have commonly got the name of hypotheses,
or theories' And the invention of a hypo-
thesis, founded on some slight probabilities,
which accounts for many appearances of
nature, has been considered as the highest
attainment of a philosopher. If the hypo-
thesis hangs well together, is embellished
by a lively imagination, and serves to ac-
count for common appearances, it is con-
sidered by many as having all the qualities
that should recommend it to our belief,
and all that ought to be required in a philo-
sophical system.

There is such proneness in men of genius
to invent hypotheses, and in others to
acquiesce in them, as the utmost which the
human faculties can atlain in philosophy,
that it is of the last consequence to the pro-
gress of real knowledge, that men should
have a clear and distinct understanding of
the nature of hypotheses in philosophy, and
of the regard that is due to them.

Although some conjectures may have a
considerable degree of probability, yet it is
evidently in the nature of conjecture to be
uncertain. In every case the assent ought
to be proportioned to the evidence ; for to
believe firmly what has but a small degree
of probability, is a manifest abuse of our
understanding. Now, though we may, in
mnny cases, form very "probable conjectures
concerning the works of men, every conjec-
ture we can form with regard to the works
of God has as little probability as the con-
jectures of a child with regard to the works
of a man.

The wisdom of God exceeds that of the
wisest man, more than his wisdom exceeds
that of a child. If a child were to conjec-
ture how an army is to be formed in the
day of battle — how a city is to be fortified,
or a state governed — what chance has he
to guess right ? As little chance has the
wisest man when he pretends to conjecture
how the planets move in their courses, how
the sea ebbs and flows, and how our minds
act upon our bodies. [49]

If a thousand of the greatest wits that
ever the world produced were, without any
previous knowledge in anatomy, to sit down
and contrive how, and by what internal
organs, the various functions of the human
body are carried on, how the blood is made
to circulate and the limbs to move, they
would not, in a thousand years, hit upon any-
thing like the truth.

Of all the discoveries that have been

["48 -50]

See above, note *, p. 97, b. — H.

made concerning the inward structure of
the human body, never one was made by
conjecture. Accurate observations of ana-
tomists have brought to light innumerable
artifices of Nature in the contrivance of this
machine of the human body, which we can-
not but admire as excellently adapted to
their several purposes. But the most saga-
cious physiologist never dreamed of them
till they were discovered. On the other
hand, innumerable conjectures, formed in
different ages, with regard to the structure
of the body, have been confuted by obser-
vation, and none ever confirmed.

What we have said of the internal struc-
ture of the human body, may be said, with
justice, of every other part of the works of
God, wherein any real discovery has been
made. Such discoveries have always been
made by patient observation, by accurate
experiments, or by conclusions drawn by
strict reasoning from observations and ex-
periments ; and such discoveries have always
tended to refute, but not to confirm, the
theories and hypotheses which ingenious
men have invented.

As this is a fact confirmed by the history
of philosophy in all past ages, it ought to
have taught men, long ago, to treat with
just contempt hypotheses in every branch
of philosophy, and to despair of ever ad-
vancing real knowledge in that way. The
Indian philosopher, being at a loss to know
how the earth was supported, invented the
hypothesis of a huge elephant; and this
elephant he supposed to stand upon the
back of a huge tortoise. This hypothesis,
however ridiculous it appears to us, might
seem very reasonable [50] toother Indians,
who knew no more than the inventor of it ;
and the same will be the fate of all hypo-
theses invented by men to account for the
works of God. They may have a decent
and plausible appearance to those who are
not more knowing than the inventor ; but,
when men come to be more enlightened,
they will always appear ridiculous and

This has been the case with regard to
hypotheses that have been revered by the
most enlightened part of mankind for hun-
dreds of years ; and it will always be the
case to the end of the world. For, until
the wisdom of men bear some proportion to
the wisdom of God, their attempts to find
out the structure of his works, by the force
of their wit and genius, will be vain.

The finest productions of human art are
immensely short of the meanest works of
Nature. The nicest artist cannot make a
feather or the leaf of a tree. Human
workmanship will never bear a comparison
with divine. Conjectures and hypotheses
are the invention and the workmanship of
men, and must bear proportion to the capa-




city and skill of the inventor; and, there-
fore, will always be very unlike to the
works of God, which it is the business of
philosophy to discover.

The world has been so long befooled by
hypotheses in all parts of philosophy, that
it is of the utmost consequence to every
man who would make any progress in real
knowledge, to treat them with just con-
tempt, as the reveries of vain and fanciful
men, whose pride makes them conceive them-
selves able to unfold the mysteries of nature
by the force of their genius. A learned man,
in an epistle to Des Cartes, has the follow-
ing observation, which very much deserved
the attention of that philosopher, and of all
that come after him : — " When men, sit-
ting in their closet, and consulting only
their books, attempt disquisitions into nature,
they may, indeed, tell how they would have
made the world, if God had given them that
in commission ; that is, they may describe
[51] chimeras, which correspond with the
imbecility of their own minds, no less than
the admirable beauty of the universe cor-
responds with the infinite perfection of its
Creator ; but without an understanding
truly divine, they can never form such an
idea to themselves as the Deity had in
creating things."

Let us, therefore, lay down this as a
fundamental principle in our inquiries into
the structure of the mind and its opera-
tions — that no regard is due to the conjec-
tures or hypotheses of philosophers, how-
ever ancient, however generally received.
Let us accustom ourselves to try every
opinion by the touchstone of fact and ex-
perience. What can fairly be deduced
from facts duly observed or sufficiently at-
tested, is genuine and pure ; it is the voice
of God, and no fiction of human imagina-

The first rule of philosophising laid down
by the great Newton, is this : — Causas re-
rum naturalium, non plurt$ admitti debere,
quam quee et veree sint, et earum phceno
menis explicnndis sufficiant. u No more
causes, nor any other causes of natural
effects, ought to be admitted, but such as
are both true, and are sufficient for ex-
plaining their appearances/* This is a golden
rule ; it is the true and proper test, by
which what is sound and solid in philoso-
phy may be distinguished from what is hol-
low and vain.*

If a philosopher, therefore, pretends to
shew us the cause of any natural effect,
whether relating to matter or to mind, let
us first consider whether there is sufficient

• For this rule we are not indebted to Newton.
It is only the old law of parcimony, and that ambigu-
ous y expressed. For, in their plain meaning, the
words " et rcree smt" are redundant ; or what follows is
redundant, and the whole rule a barren truism,— H.

evidence that the cause he assigns doss
really exist. If there is not, reject it with
disdain, as a fiction which ought to have no
place in genuine philosophy. If the cause
assigned really exists, consider, in the next
place, whether the effect it is brought to
explain necessarily follows from it. Un-
less it has these two conditions, it is good
for nothing.

When Newton had shewn the admirable
effects of gravitation in our planetary sys-
tem, he must have felt a strong desire to
know [52] its cause. He could have in-
vented a hypothesis for this purpose, as
many had done before him. But his phi-
losophy was of another complexion. Let
us hear what he says : Rationem harum
ffravitatis proprielatum ex pkeenomenis rfm
pitui deduce? e, et hypotheses non Jingo.
Quit-quid enim eor-phecnomenis non dedueU
tur hypothesis vocanda est. Et hypotheses^
seu melaphytkce, seu physices, seu qualila-
tum occultaium, seu mech-trucee, in phtloso-
phia experimentali locum non habent.



It is natural to men to judge of things
less known, by some similitude they ob-
serve, or think they observe, between them
and things more familiar or better known.
In many cases, we have no better way of
judging. And, where the things compared
have really a great similitude in their na-
ture, when there is reason to think that they
are subject to the same laws, there may be
a considerable degree of probability in con-
clusions drawn from analogy.

Thus, we may observe a very great si-
militude between this earth which we in-
habit, and the other planets, Saturn, Ju-
piter, Mars, Venus, and Mercury. They
all revolve round the sun, as the earth
does, although at different distances and
in different periods. They borrow all their
light from the sun, as the earth does.
Several of them are known to revolve round
their axis like the earth, and, by that
means, must have a like succession of day
and night. Some of them have moons,
that serve to give them light in the absence
of the sun, as our moon does to us. They
are all, in their motions, subject to the
same law of gravitation, as the earth is.
From all this similitude, it is not unrea-
sonable to think, that those planets may,
like our earth, be the habitation of va-
rious [53] orders of living creatures. There
is some probability in this conclusion from

In medicine, physicians must, for the
most part, be directed in their prescriptions




by analogy. The constitution of one human
body is so like, to that of another that it is
reasonable to think that what is the cause
of health or sickness to one, may have the
same effect upon another. And this ge-
nerally is found true, though not without
some exceptions.

In politics we reason, for the most part,
from analogy. The constitution of human
nature is so similar in different societies or
commonwealths, that the causes of peace
and war, of tranquillity and sedition, of
riches and poverty, of improvement and
degeneracy, are much the same in all.

Analogical reasoning, therefore, is not,
in all cases, to be rejected. It may afford
a greater or a less degree of probability,
according as the things compared are more
or less similar in their nature. But it
ought to be observed, that, as this kind of
reasoning can afford only probable evidence
at best ; so, unless great caution be used,
we are apt to be led into error by it. For
men are naturally disposed to conceive a
greater similitude in things than there
really is.

To give an instance of this : Anatomists,
in ancient ages, seldom dissected human
bodies ; but very often the bodies of those
quadrupeds whose internal structure was
thought to approach nearest to that of the
human body. Modern anatomists have
discovered many mistakes the ancients
were led into, by their conceiving a greater
similitude between the structure of men
and of some beasts than there is in reality.
By this, and many other instances that
might be given, it appears that conclusions
built on analogy stand on a slippery founda-
tion ; and that we ought never to rest upon
evidence of this kind, when we can have
more direct evidence. [54]

I know no author who has made a more
just and a more happy use of this mode of
reasoning than Bishop Butler, in his " Ana-
logy of Religion, Natural and Revealed, to
the Constitution and Course of Nature."
In that excellent work the author does not
ground any of the truths of religion upon
analogy, as their proper evidence. He
only makes use of analogy to answer objec-
tions against them. When objections are
made against the truths of religion, which
may be made with equal strength against
what we know to be true in the course
of nature, such objections can have no

Analogical reasoning, therefore, may be
of excellent use in answering objections
against truths which have other evidence.
It may likewise give a greater or a less
degree of probability in cases where we can
find no other evidence. But all arguments,
drawn from analogy, are still the weaker,
the greater disparity there is between the
f54. 55]

things compared ; and, therefore, must be
weakest of all when we compare body wiili
mind, because there are no two things in
nature more unlike.

There is no subject in which men have
always been so prone to form their notions
by analogies of this kind, as in what re-
lates to the mind. We form an early ac-
quaintance with material things by means
of our senses, and are bred up in a con-
stant familiarity with them. Hence we
are apt to measure all things by them ; and
to ascribe to things most remote from mat-
ter, the qualities that belong to material
things. It is for this reason, that man-
kind have, in all ages, been so prone to
conceive the mind itself to be some sub-
tile kind of matter : that they have been
'disposed to ascribe human figure and hu-
man organs, not only to angels, but even
to the Deity. Though we are conscious of
the operations of our own minds when they
are exerted, and are capable of attending
to them, so as to form a distinct notion of
them, this is so difficult a work to men
whose attention is constantly solicited by
external objects, that we give them names
from things that are familiar, and which
[55] are conceived to have some similitude
to them ; and the notions we form of them

Online LibraryThomas ReidThe works of Thomas Reid, D.D.; now fully collected, with selections from his umpublished letters → online text (page 53 of 114)