PART IV.

OF THE EARTH.

CLXXXVIII. Of what is to be borrowed from disquisitions on animals

and man to advance the knowledge of material objects.

I should add nothing farther to this the Fourth Part of the

Principles of Philosophy, did I purpose carrying out my original

design of writing a Fifth and Sixth Part, the one treating of things

possessed of life, that is, animals and plants, and the other of

man. But because I have not yet acquired sufficient knowledge of all

the matters of which I should desire to treat in these two last

parts, and do not know whether I shall ever have sufficient leisure

to finish them, I will here subjoin a few things regarding the

objects of our senses, that I may not, for the sake of the latter,

delay too long the publication of the former parts, or of what may

be desiderated in them, which I might have reserved for explanation

in those others: for I have hitherto described this earth, and

generally the whole visible world, as if it were merely a machine in

which there was nothing at all to consider except the figures and

motions of its parts, whereas our senses present to us many other

things, for example colours, smells, sounds, and the like, of which,

if I did not speak at all, it would be thought I had omitted the

explication of the majority of the objects that are in nature.

CLXXXIX. What perception (SENSUS) is, and how we perceive.

We must know, therefore, that although the human soul is united to

the whole body, it has, nevertheless, its principal seat in the

brain, where alone it not only understands and imagines, but also

perceives; and this by the medium of the nerves, which are extended

like threads from the brain to all the other members, with which

they are so connected that we can hardly touch any one of them

without moving the extremities of some of the nerves spread over it;

and this motion passes to the other extremities of those nerves

which are collected in the brain round the seat of the soul,

[Footnote: *** FOOTNOTE NOT VISIBLE IN PAGE IMAGE (#98, Text p 195)]

as I have already explained with sufficient minuteness in the fourth

chapter of the Dioptrics. But the movements which are thus excited

in the brain by the nerves variously affect the soul or mind, which

is intimately conjoined with the brain, according to the diversity

of the motions themselves. And the diverse affections of the mind or

thoughts that immediately arise from these motions, are called

perceptions of the senses (SENSUUM PERCEPTIONES), or, as we commonly

speak, sensations (SENSUS).

CXC. Of the distinction of the senses; and, first, of the internal,

that is, of the affections of the mind (passions), and the natural

appetites.

The varieties of these sensations depend, firstly, on the diversity

of the nerves themselves, and, secondly, of the movements that are

made in each nerve. We have not, however, as many different senses

as there are nerves. We can distinguish but seven principal classes

of nerves, of which two belong to the internal, and the other five

to the external senses. The nerves which extend to the stomach, the

oesophagus, the fauces, and the other internal parts that are

subservient to our natural wants, constitute one of our internal

senses. This is called the natural appetite (APPETITUS NATURALIS).

The other internal sense, which embraces all the emotions

(COMMOTIONES) of the mind or passions, and affections, as joy,

sadness, love, hate, and the like, depends upon the nerves which

extend to the heart and the parts about the heart, and are

exceedingly small; for, by way of example, when the blood happens to

be pure and well tempered, so that it dilates in the heart more

readily and strongly than usual, this so enlarges and moves the

small nerves scattered around the orifices, that there is thence a

corresponding movement in the brain, which affects the mind with a

certain natural feeling of joy; and as often as these same nerves

are moved in the same way, although this is by other causes, they

excite in our mind the same feeling (sensus, sentiment). Thus, the

imagination of the enjoyment of a good does not contain in itself

the feeling of joy, but it causes the animal spirits to pass from

the brain to the muscles in which these nerves are inserted; and

thus dilating the orifices of the heart, it also causes these small

nerves to move in the way appointed by nature to afford the

sensation of joy. Thus, when we receive news, the mind first of all

judges of it, and if the news be good, it rejoices with that

intellectual joy (GAUDIUM INTELLECTUALE) which is independent of any

emotion (COMMOTIO) of the body, and which the Stoics did not deny to

their wise man [although they supposed him exempt from all passion].

But as soon as this joy passes from the understanding to the

imagination, the spirits flow from the brain to the muscles that are

about the heart, and there excite the motion of the small nerves, by

means of which another motion is caused in the brain, which affects

the mind with the sensation of animal joy (LAETITIA ANIMALIS). On

the same principle, when the blood is so thick that it flows but

sparingly into the ventricles of the heart, and is not there

sufficiently dilated, it excites in the same nerves a motion quite

different from the preceding, which, communicated to the brain,

gives to the mind the sensation of sadness, although the mind itself

is perhaps ignorant of the cause of its sadness. And all the other

causes which move these nerves in the same way may also give to the

mind the same sensation. But the other movements of the same nerves

produce other effects, as the feelings of love, hate, fear, anger,

etc., as far as they are merely affections or passions of the mind;

in other words, as far as they are confused thoughts which the mind

has not from itself alone, but from its being closely joined to the

body, from which it receives impressions; for there is the widest

difference between these passions and the distinct thoughts which we

have of what ought to be loved, or chosen, or shunned, etc.,

[although these are often enough found together]. The natural

appetites, as hunger, thirst, and the others, are likewise

sensations excited in the mind by means of the nerves of the

stomach, fauces, and other parts, and are entirely different from

the will which we have to eat, drink, [and to do all that which we

think proper for the conservation of our body]; but, because this

will or appetition almost always accompanies them, they are

therefore named appetites.

CXCI. Of the external senses; and first of touch.

We commonly reckon the external senses five in number, because there

are as many different kinds of objects which move the nerves and

their organs, and an equal number of kinds of confused thoughts

excited in the soul by these emotions. In the first place, the

nerves terminating in the skin of the whole body can be touched

through this medium by any terrene objects whatever, and moved by

these wholes, in one way by their hardness, in another by their

gravity, in a third by their heat, in a fourth by their humidity,

etc.--and in as many diverse modes as they are either moved or

hindered from their ordinary motion, to that extent are diverse

sensations excited in the mind, from which a corresponding number of

tactile qualities derive their appellations. Besides this, when

these nerves are moved a little more powerfully than usual, but not

nevertheless to the degree by which our body is in any way hurt,

there thus arises a sensation of titillation, which is naturally

agreeable to the mind, because it testifies to it of the powers of

the body with which it is joined, [in that the latter can suffer the

action causing this titillation, without being hurt]. But if this

action be strong enough to hurt our body in any way, this gives to

our mind the sensation of pain. And we thus see why corporeal

pleasure and pain, although sensations of quite an opposite

character, arise nevertheless from causes nearly alike.

CXCII. Of taste.

In the second place, the other nerves scattered over the tongue and

the parts in its vicinity are diversely moved by the particles of

the same bodies, separated from each other and floating in the

saliva in the mouth, and thus cause sensations of diverse tastes

according to the diversity of figure in these particles. [Footnote:

In the French this section begins, "Taste, after touch the grossest

of the senses," etc.]

CXCIII. Of smell.

Thirdly, two nerves also or appendages of the brain, for they do not

go beyond the limits of the skull, are moved by the particles of

terrestrial bodies, separated and flying in the air, not indeed by

all particles indifferently, but by those only that are sufficiently

subtle and penetrating to enter the pores of the bone we call the

spongy, when drawn into the nostrils, and thus to reach the nerves.

From the different motions of these particles arise the sensations

of the different smells.

CXCIV. Of hearing.

Fourthly, there are two nerves within the ears, so attached to three

small bones that are mutually sustaining, and the first of which

rests on the small membrane that covers the cavity we call the

tympanum of the ear, that all the diverse vibrations which the

surrounding air communicates to this membrane are transmitted to the

mind by these nerves, and these vibrations give rise, according to

their diversity, to the sensations of the different sounds.

CXCV. Of sight.

Finally, the extremities of the optic nerves, composing the coat in

the eyes called the retina, are not moved by the air nor by any

terrestrial object, but only by the globules of the second element,

whence we have the sense of light and colours: as I have already at

sufficient length explained in the Dioptrics and treatise of

Meteors. [Footnote: In the French this section begins, "Finally,

sight is the most subtle of all the senses," etc.]

CXCVI. That the soul perceives only in so far as it is in the

brain.

It is clearly established, however, that the soul does not perceive

in so far as it is in each member of the body, but only in so far as

it is in the brain, where the nerves by their movements convey to it

the diverse actions of the external objects that touch the parts of

the body in which they are inserted. For, in the first place, there

are various maladies, which, though they affect the brain alone, yet

bring disorder upon, or deprive us altogether of the use of, our

senses, just as sleep, which affects the brain only, and yet takes

from us daily during a great part of our time the faculty of

perception, which afterwards in our waking state is restored to us.

The second proof is, that though there be no disease in the brain,

[or in the members in which the organs of the external senses are],

it is nevertheless sufficient to take away sensation from the part

of the body where the nerves terminate, if only the movement of one

of the nerves that extend from the brain to these members be

obstructed in any part of the distance that is between the two. And

the last proof is, that we sometimes feel pain as if in certain of

our members, the cause of which, however, is not in these members

where it is felt, but somewhere nearer the brain, through which the

nerves pass that give to the mind the sensation of it. I could

establish this fact by innumerable experiments; I will here,

however, merely refer to one of them. A girl suffering from a bad

ulcer in the hand, had her eyes bandaged whenever the surgeon came

to visit her, not being able to bear the sight of the dressing of

the sore; and, the gangrene having spread, after the expiry of a few

days the arm was amputated from the elbow [without the girl's

knowledge]; linen cloths tied one above the other were substituted

in place of the part amputated, so that she remained for some time

without knowing that the operation had been performed, and meanwhile

she complained of feeling various pains, sometimes in one finger of

the hand that was cut off, and sometimes in another. The only

explanation of this is, that the nerves which before stretched

downwards from the brain to the hand, and then terminated in the arm

close to the elbow, were there moved in the same way as they

required to be moved before in the hand for the purpose of

impressing on the mind residing in the brain the sensation of pain

in this or that finger. [And this clearly shows that the pain of the

hand is not felt by the mind in so far as it is in the hand, but in

so far as it is in the brain.]

CXCVII. That the nature of the mind is such that from the motion

alone of body the various sensations can be excited in it.

In the next place, it can be proved that our mind is of such a

nature that the motions of the body alone are sufficient to excite

in it all sorts of thoughts, without it being necessary that these

should in any way resemble the motions which give rise to them, and

especially that these motions can excite in it those confused

thoughts called sensations (SENSUS, SENSATIONES). For we see that

words, whether uttered by the voice or merely written, excite in our

minds all kinds of thoughts and emotions. On the same paper, with

the same pen and ink, by merely moving the point of the pen over the

paper in a particular way, we can trace letters that will raise in

the minds of our readers the thoughts of combats, tempests, or the

furies, and the passions of indignation and sorrow; in place of

which, if the pen be moved in another way hardly different from the

former, this slight change will cause thoughts widely different from

the above, such as those of repose, peace, pleasantness, and the

quite opposite passions of love and joy. Some one will perhaps

object that writing and speech do not immediately excite in the mind

any passions, or imaginations of things different from the letters

and sounds, but afford simply the knowledge of these, on occasion of

which the mind, understanding the signification of the words,

afterwards excites in itself the imaginations and passions that

correspond to the words. But what will be said of the sensations of

pain and titillation? The motion merely of a sword cutting a part of

our skin causes pain, [but does not on that account make us aware of

the motion or figure of the sword]. And it is certain that this

sensation of pain is not less different from the motion that causes

it, or from that of the part of our body which the sword cuts, than

are the sensations we have of colour, sound, odour, or taste. On

this ground we may conclude that our mind is of such a nature that

the motions alone of certain bodies can also easily excite in it all

the other sensations, as the motion of a sword excites in it the

sensation of pain.

CXCVIII. That by our senses we know nothing of external objects

beyond their figure [or situation], magnitude, and motion.

Besides, we observe no such difference between the nerves as to lead

us to judge that one set of them convey to the brain from the organs

of the external senses anything different from another, or that

anything at all reaches the brain besides the local motion of the

nerves themselves. And we see that local motion alone causes in us

not only the sensation of titillation and of pain, but also of light

and sounds. For if we receive a blow on the eye of sufficient force

to cause the vibration of the stroke to reach the retina, we see

numerous sparks of fire, which, nevertheless, are not out of our

eye; and when we stop our ear with our finger, we hear a humming

sound, the cause of which can only proceed from the agitation of the

air that is shut up within it. Finally, we frequently observe that

heat [hardness, weight], and the other sensible qualities, as far as

they are in objects, and also the forms of those bodies that are

purely material, as, for example, the forms of fire, are produced in

them by the motion of certain other bodies, and that these in their

turn likewise produce other motions in other bodies. And we can

easily conceive how the motion of one body may be caused by that of

another, and diversified by the size, figure, and situation of its

parts, but we are wholly unable to conceive how these same things

(viz., size, figure, and motion), can produce something else of a

nature entirely different from themselves, as, for example, those

substantial forms and real qualities which many philosophers suppose

to be in bodies; nor likewise can we conceive how these qualities or

forms possess force to cause motions in other bodies. But since we

know, from the nature of our soul, that the diverse motions of body

are sufficient to produce in it all the sensations which it has, and

since we learn from experience that several of its sensations are in

reality caused by such motions, while we do not discover that

anything besides these motions ever passes from the organs of the

external senses to the brain, we have reason to conclude that we in

no way likewise apprehend that in external objects, which we call

light, colour, smell, taste, sound, heat or cold, and the other

tactile qualities, or that which we call their substantial forms,

unless as the various dispositions of these objects which have the

power of moving our nerves in various ways. [Footnote: "the diverse

figures, situations, magnitudes, and motions of their parts."--

French.]

CXCIX. That there is no phenomenon of nature whose explanation has

been omitted in this treatise.

And thus it may be gathered, from an enumeration that is easily

made, that there is no phenomenon of nature whose explanation has

been omitted in this treatise; for beyond what is perceived by the

senses, there is nothing that can be considered a phenomenon of

nature. But leaving out of account motion, magnitude, figure, [and

the situation of the parts of each body], which I have explained as

they exist in body, we perceive nothing out of us by our senses

except light, colours, smells, tastes, sounds, and the tactile

qualities; and these I have recently shown to be nothing more, at

least so far as they are known to us, than certain dispositions of

the objects, consisting in magnitude, figure, and motion.

CC. That this treatise contains no principles which are not

universally received; and that this philosophy is not new, but of

all others the most ancient and common.

But I am desirous also that it should be observed that, though I

have here endeavoured to give an explanation of the whole nature of

material things, I have nevertheless made use of no principle which

was not received and approved by Aristotle, and by the other

philosophers of all ages; so that this philosophy, so far from being

new, is of all others the most ancient and common: for I have in

truth merely considered the figure, motion, and magnitude of bodies,

and examined what must follow from their mutual concourse on the

principles of mechanics, which are confirmed by certain and daily

experience. But no one ever doubted that bodies are moved, and that

they are of various sizes and figures, according to the diversity of

which their motions also vary, and that from mutual collision those

somewhat greater than others are divided into many smaller, and thus

change figure. We have experience of the truth of this, not merely

by a single sense, but by several, as touch, sight, and hearing: we

also distinctly imagine and understand it. This cannot be said of

any of the other things that fall under our senses, as colours,

sounds, and the like; for each of these affects but one of our

senses, and merely impresses upon our imagination a confused image

of itself, affording our understanding no distinct knowledge of what

it is.

CCI. That sensible bodies are composed of insensible particles.

But I allow many particles in each body that are perceived by none

of our senses, and this will not perhaps be approved of by those who

take the senses for the measure of the knowable. [We greatly wrong

human reason, however, as appears to me, if we suppose that it does

not go beyond the eye-sight]; for no one can doubt that there are

bodies so small as not to be perceptible by any of our senses,

provided he only consider what is each moment added to those bodies

that are being increased little by little, and what is taken from

those that are diminished in the same way. A tree increases daily,

and it is impossible to conceive how it becomes greater than it was

before, unless we at the same time conceive that some body is added

to it. But who ever observed by the senses those small bodies that

are in one day added to a tree while growing? Among the philosophers

at least, those who hold that quantity is indefinitely divisible,

ought to admit that in the division the parts may become so small as

to be wholly imperceptible. And indeed it ought not to be a matter

of surprise, that we are unable to perceive very minute bodies; for

the nerves that must be moved by objects to cause perception are not

themselves very minute, but are like small cords, being composed of

a quantity of smaller fibres, and thus the most minute bodies are

not capable of moving them. Nor do I think that any one who makes

use of his reason will deny that we philosophize with much greater

truth when we judge of what takes place in those small bodies which

are imperceptible from their minuteness only, after the analogy of

what we see occurring in those we do perceive, [and in this way

explain all that is in nature, as I have essayed to do in this

treatise], than when we give an explanation of the same things by

inventing I know not what novelties, that have no relation to the

things we actually perceive, [as first matter, substantial forms,

and all that grand array of qualities which many are in the habit of

supposing, each of which is more difficult to comprehend than all

that is professed to be explained by means of them].

CCII. That the philosophy of Democritus is not less different from

ours than from the common. [Footnote: "that of Aristotle or the

others."--French.]

But it may be said that Democritus also supposed certain corpuscles

that were of various figures, sizes, and motions, from the heaping

together and mutual concourse of which all sensible bodies arose;

and, nevertheless, his mode of philosophizing is commonly rejected

by all. To this I reply that the philosophy of Democritus was never

rejected by any one, because he allowed the existence of bodies

smaller than those we perceive, and attributed to them diverse

sizes, figures, and motions, for no one can doubt that there are in

reality such, as we have already shown; but it was rejected, in the

first place, because he supposed that these corpuscles were

indivisible, on which ground I also reject it; in the second place,

because he imagined there was a vacuum about them, which I show to

be impossible; thirdly, because he attributed gravity to these

bodies, of which I deny the existence in any body, in so far as a

body is considered by itself, because it is a quality that depends

on the relations of situation and motion which several bodies bear

to each other; and, finally, because he has not explained in

particular how all things arose from the concourse of corpuscles

alone, or, if he gave this explanation with regard to a few of them,

his whole reasoning was far from being coherent, [or such as would

warrant us in extending the same explanation to the whole of

nature]. This, at least, is the verdict we must give regarding his

philosophy, if we may judge of his opinions from what has been

handed down to us in writing. I leave it to others to determine

whether the philosophy I profess possesses a valid coherency, [and

whether on its principles we can make the requisite number of

deductions; and, inasmuch as the consideration of figure, magnitude,

and motion has been admitted by Aristotle and by all the others, as

well as by Democritus, and since I reject all that the latter has

supposed, with this single exception, while I reject generally all

that has been supposed by the others, it is plain that this mode of

philosophizing has no more affinity with that of Democritus than of

any other particular sect].

CCIII. How we may arrive at the knowledge of the figures,

[magnitudes], and motions of the insensible particles of bodies.

But, since I assign determinate figures, magnitudes, and motions to

the insensible particles of bodies, as if I had seen them, whereas I

admit that they do not fall under the senses, some one will perhaps

demand how I have come by my knowledge of them. [To this I reply,

that I first considered in general all the clear and distinct

notions of material things that are to be found in our

understanding, and that, finding no others except those of figures,

magnitudes, and motions, and of the rules according to which these

three things can be diversified by each other, which rules are the

principles of geometry and mechanics, I judged that all the

knowledge man can have of nature must of necessity be drawn from

this source; because all the other notions we have of sensible

things, as confused and obscure, can be of no avail in affording us

the knowledge of anything out of ourselves, but must serve rather to

impede it]. Thereupon, taking as my ground of inference the simplest

and best known of the principles that have been implanted in our

minds by nature, I considered the chief differences that could

possibly subsist between the magnitudes, and figures, and situations

of bodies insensible on account of their smallness alone, and what

sensible effects could be produced by their various modes of coming

into contact; and afterwards, when I found like effects in the

bodies that we perceive by our senses, I judged that they could have

been thus produced, especially since no other mode of explaining

them could be devised. And in this matter the example of several

bodies made by art was of great service to me: for I recognize no

difference between these and natural bodies beyond this, that the

effects of machines depend for the most part on the agency of

certain instruments, which, as they must bear some proportion to the

hands of those who make them, are always so large that their figures

and motions can be seen; in place of which, the effects of natural

bodies almost always depend upon certain organs so minute as to

escape our senses. And it is certain that all the rules of mechanics

belong also to physics, of which it is a part or species, [so that

all that is artificial is withal natural]: for it is not less

natural for a clock, made of the requisite number of wheels, to mark

the hours, than for a tree, which has sprung from this or that seed,

to produce the fruit peculiar to it. Accordingly, just as those who

are familiar with automata, when they are informed of the use of a

machine, and see some of its parts, easily infer from these the way

in which the others, that are not seen by them, are made; so from

considering the sensible effects and parts of natural bodies, I have

essayed to determine the character of their causes and insensible

parts.

CCIV. That, touching the things which our senses do not perceive,

it is sufficient to explain how they can be, [and that this is all

that Aristotle has essayed].

But here some one will perhaps reply, that although I have supposed

causes which could produce all natural objects, we ought not on this

account to conclude that they were produced by these causes; for,

just as the same artisan can make two clocks, which, though they

both equally well indicate the time, and are not different in

outward appearance, have nevertheless nothing resembling in the

composition of their wheels; so doubtless the Supreme Maker of

things has an infinity of diverse means at his disposal, by each of

which he could have made all the things of this world to appear as

we see them, without it being possible for the human mind to know

which of all these means he chose to employ. I most freely concede

this; and I believe that I have done all that was required, if the

causes I have assigned are such that their effects accurately

correspond to all the phenomena of nature, without determining

whether it is by these or by others that they are actually produced.

And it will be sufficient for the use of life to know the causes

thus imagined, for medicine, mechanics, and in general all the arts

to which the knowledge of physics is of service, have for their end

only those effects that are sensible, and that are accordingly to be

reckoned among the phenomena of nature. [Footnote: "have for their

end only to apply certain sensible bodies to each other in such a

way that, in the course of natural causes, certain sensible effects

may be produced; and we will be able to accomplish this quite as

well by considering the series of certain causes thus imagined,

although false, as if they were the true, since this series is

supposed similar as far as regards sensible effects."-French.]

And lest it should be supposed that Aristotle did, or professed to

do, anything more than this, it ought to be remembered that he

himself expressly says, at the commencement of the seventh chapter

of the first book of the Meteorologies, that, with regard to things

which are not manifest to the senses, he thinks to adduce sufficient

reasons and demonstrations of them, if he only shows that they may

be such as he explains them. [Footnote: words in Greek]

CCV. That nevertheless there is a moral certainty that all the

things of this world are such as has been here shown they may be.

But nevertheless, that I may not wrong the truth by supposing it

less certain than it is, I will here distinguish two kinds of

certitude. The first is called moral, that is, a certainty

sufficient for the conduct of life, though, if we look to the

absolute power of God, what is morally certain may be false. [Thus,

those who never visited Rome do not doubt that it is a city of

Italy, though it might be that all from whom they got their

information were deceived]. Again, if any one, wishing to decipher a

letter written in Latin characters that are not placed in regular

order, bethinks himself of reading a B wherever an A is found, and a

C wherever there is a B, and thus of substituting in place of each

letter the one which follows it in the order of the alphabet, and if

by this means he finds that there are certain Latin words composed

of these, he will not doubt that the true meaning of the writing is

contained in these words, although he may discover this only by

conjecture, and although it is possible that the writer of it did

not arrange the letters on this principle of alphabetical order, but

on some other, and thus concealed another meaning in it: for this is

so improbable [especially when the cipher contains a number of

words] as to seem incredible. But they who observe how many things

regarding the magnet, fire, and the fabric of the whole world, are

here deduced from a very small number of principles, though they

deemed that I had taken them up at random and without grounds, will

yet perhaps acknowledge that it could hardly happen that so many

things should cohere if these principles were false.

CCVI. That we possess even more than a moral certainty of it.

Besides, there are some, even among natural, things which we judge

to be absolutely certain. [Absolute certainty arises when we judge

that it is impossible a thing can be otherwise than as we think it].

This certainty is founded on the metaphysical ground, that, as God

is supremely good and the source of all truth, the faculty of

distinguishing truth from error which he gave us, cannot be

fallacious so long as we use it aright, and distinctly perceive

anything by it. Of this character are the demonstrations of

mathematics, the knowledge that material things exist, and the clear

reasonings that are formed regarding them. The results I have given

in this treatise will perhaps be admitted to a place in the class of

truths that are absolutely certain, if it be considered that they

are deduced in a continuous series from the first and most

elementary principles of human knowledge; especially if it be

sufficiently understood that we can perceive no external objects

unless some local motion be caused by them in our nerves, and that

such motion cannot be caused by the fixed stars, owing to their

great distance from us, unless a motion be also produced in them and

in the whole heavens lying between them and us: for these points

being admitted, all the others, at least the more general doctrines

which I have advanced regarding the world or earth [e. g., the

fluidity of the heavens, Part III., Section XLVI.], will appear to

be almost the only possible explanations of the phenomena they

present.

CCVII. That, however, I submit all my opinions to the authority of

the church.

Nevertheless, lest I should presume too far, I affirm nothing, but

submit all these my opinions to the authority of the church and the

judgment of the more sage; and I desire no one to believe anything I

may have said, unless he is constrained to admit it by the force and

evidence of reason.

Selections from the Principles of Philosophy · 第 4 / 4 章