Part II._Ethics（#3800）

ON THE NATURE AND ORIGIN OF THE MIND

PREFACE

I now pass on to explaining the results, which must

necessarily follow from the essence of God, or of the eternal and

infinite being; not, indeed, all of them (for we proved in Part

i., Prop. xvi., that an infinite number must follow in an

infinite number of ways), but only those which are able to lead

us, as it were by the hand, to the knowledge of the human mind

and its highest blessedness.

DEFINITIONS

DEFINITION I. By body I mean a mode which expresses in a certain

determinate manner the essence of God, in so far as he is

considered as an extended thing. (See Pt. i., Prop. xxv.,

Coroll.)

DEFINITION II. I consider as belonging to the essence of a thing

that, which being given, the thing is necessarily given also,

and, which being removed, the thing is necessarily removed also;

in other words, that without which the thing, and which itself

without the thing, can neither be nor be conceived.

DEFINITION III. By idea, I mean the mental conception which is

formed by the mind as a thinking thing.

Explanation.--I say conception rather than perception, because

the word perception seems to imply that the mind is passive in

respect to the object; whereas conception seems to express an

activity of the mind.

DEFINITION IV. By an adequate idea, I mean an idea which, in so

far as it is considered in itself, without relation to the

object, has all the properties or intrinsic marks of a true idea.

Explanation.--I say intrinsic, in order to exclude that mark

which is extrinsic, namely, the agreement between the idea and

its object (ideatum).

DEFINITION V. Duration is the indefinite continuance of

existing.

Explanation.--I say indefinite, because it cannot be

determined through the existence itself of the existing thing, or

by its efficient cause, which necessarily gives the existence of

the thing, but does not take it away.

DEFINITION VI. Reality and perfection I use as synonymous terms.

DEFINITION VII. By particular things, I mean things which are

finite and have a conditioned existence; but if several

individual things concur in one action, so as to be all

simultaneously the effect of one cause, I consider them all, so

far, as one particular thing.

AXIOMS

I. The essence of man does not involve necessary existence, that

is, it may, in the order of nature, come to pass that this or

that man does or does not exist.

II. Man thinks.

III. Modes of thinking, such as love, desire, or any other of

the passions, do not take place, unless there be in the same

individual an idea of the thing loved, desired, &c. But the idea

can exist without the presence of any other mode of thinking.

IV. We perceive that a certain body is affected in many ways.

V. We feel and perceive no particular things, save bodies and

modes of thought.

N.B. The Postulates are given after the conclusion of Prop.

xiii.

PROPOSITIONS

PROP. I. Thought is an attribute of God, or God is a thinking

thing.

Proof.--Particular thoughts, or this and that thought, are

modes which, in a certain conditioned manner, express the nature

of God (Pt. i., Prop. xxv., Coroll.). God therefore possesses

the attribute (Pt. i., Def. v.) of which the concept is involved

in all particular thoughts, which latter are conceived thereby.

Thought, therefore, is one of the infinite attributes of God,

which express God's eternal and infinite essence (Pt. i., Def.

vi.). In other words, God is a thinking thing. Q.E.D.

Note.--This proposition is also evident from the fact, that we

are able to conceive an infinite thinking being. For, in

proportion as a thinking being is conceived as thinking more

thoughts, so is it conceived as containing more reality or

perfection. Therefore a being, which can think an infinite

number of things in an infinite number of ways, is, necessarily,

in respect of thinking, infinite. As, therefore, from the

consideration of thought alone, we conceive an infinite being,

thought is necessarily (Pt. i., Deff. iv. and vi.) one of the

infinite attributes of God, as we were desirous of showing.

PROP. II. Extension is an attribute of God, or God is an

extended thing.

Proof.--The proof of this proposition is similar to that of

the last.

PROP. III. In God there is necessarily the idea not only of his

essence, but also of all things which necessarily follow from his

essence.

Proof.--God (by the first Prop. of this Part) can think an

infinite number of things in infinite ways, or (what is the same

thing, by Prop. xvi., Part i.) can form the idea of his essence,

and of all things which necessarily follow therefrom. Now all

that is in the power of God necessarily is (Pt. i., Prop. xxxv.).

Therefore, such an idea as we are considering necessarily is, and

in God alone. Q.E.D. (Part i., Prop. xv.)

Note.--The multitude understand by the power of God the free

will of God, and the right over all things that exist, which

latter are accordingly generally considered as contingent. For

it is said that God has the power to destroy all things, and to

reduce them to nothing. Further, the power of God is very often

likened to the power of kings. But this doctrine we have refuted

(Pt. i., Prop. xxxii., Corolls. i. and ii.), and we have shown

(Part i., Prop. xvi.) that God acts by the same necessity, as

that by which he understands himself; in other words, as it

follows from the necessity of the divine nature (as all admit),

that God understands himself, so also does it follow by the same

necessity, that God performs infinite acts in infinite ways. We

further showed (Part i., Prop. xxxiv.), that God's power is

identical with God's essence in action; therefore it is as

impossible for us to conceive God as not acting, as to conceive

him as non--existent. If we might pursue the subject further, I

could point out, that the power which is commonly attributed to

God is not only human (as showing that God is conceived by the

multitude as a man, or in the likeness of a man), but involves a

negation of power. However, I am unwilling to go over the same

ground so often. I would only beg the reader again and again, to

turn over frequently in his mind what I have said in Part I from

Prop. xvi. to the end. No one will be able to follow my meaning,

unless he is scrupulously careful not to confound the power of

God with the human power and right of kings.

PROP. IV. The idea of God, from which an infinite number of

things follow in infinite ways, can only be one.

Proof.--Infinite intellect comprehends nothing save the

attributes of God and his modifications (Part i., Prop. xxx.).

Now God is one (Part i., Prop. xiv., Coroll.). Therefore the

idea of God, wherefrom an infinite number of things follow in

infinite ways, can only be one. Q.E.D.

PROP. V. The actual being of ideas owns God as its cause, only

in so far as he is considered as a thinking thing, not in so far

as he is unfolded in any other attribute; that is, the ideas

both of the attributes of God and of particular things do not own

as their efficient cause their objects (ideata) or the things

perceived, but God himself in so far as he is a thinking thing.

Proof.--This proposition is evident from Prop. iii. of this

Part. We there drew the conclusion, that God can form the idea

of his essence, and of all things which follow necessarily

therefrom, solely because he is a thinking thing, and not because

he is the object of his own idea. Wherefore the actual being of

ideas owns for cause God, in so far as he is a thinking thing.

It may be differently proved as follows: the actual being of

ideas is (obviously) a mode of thought, that is (Part i., Prop.

xxv., Coroll.) a mode which expresses in a certain manner the

nature of God, in so far as he is a thinking thing, and therefore

(Part i., Prop. x.) involves the conception of no other attribute

of God, and consequently (by Part i., Ax. iv.) is not the effect

of any attribute save thought. Therefore the actual being of

ideas owns God as its cause, in so far as he is considered as a

thinking thing, &c. Q.E.D.

PROP. VI. The modes of any given attribute are caused by God, in

so far as he is considered through the attribute of which they

are modes, and not in so far as he is considered through any

other attribute.

Proof.--Each attribute is conceived through itself, without

any other (Part i., Prop. x.); wherefore the modes of each

attribute involve the conception of that attribute, but not of

any other. Thus (Part i., Ax. iv.) they are caused by God, only

in so far as he is considered through the attribute whose modes

they are, and not in so far as he is considered through any

other. Q.E.D.

Corollary.--Hence the actual being of things, which are not

modes of thought, does not follow from the divine nature, because

that nature has prior knowledge of the things. Things

represented in ideas follow, and are derived from their

particular attribute, in the same manner, and with the same

necessity as ideas follow (according to what we have shown) from

the attribute of thought.

PROP. VII. The order and connection of ideas is the same as the

order and connection of things.

Proof.--This proposition is evident from Part i., Ax. iv. For

the idea of everything that is caused depends on a knowledge of

the cause, whereof it is an effect.

Corollary.--Hence God's power of thinking is equal to his

realized power of action--that is, whatsoever follows from the

infinite nature of God in the world of extension (formaliter),

follows without exception in the same order and connection from

the idea of God in the world of thought (objective).

Note.--Before going any further, I wish to recall to mind what

has been pointed out above--namely, that whatsoever can be

perceived by the infinite intellect as constituting the essence

of substance, belongs altogether only to one substance:

consequently, substance thinking and substance extended are one

and the same substance, comprehended now through one attribute,

now through the other. So, also, a mode of extension and the

idea of that mode are one and the same thing, though expressed in

two ways. This truth seems to have been dimly recognized by

those Jews who maintained that God, God's intellect, and the

things understood by God are identical. For instance, a circle

existing in nature, and the idea of a circle existing, which is

also in God, are one and the same thing displayed through

different attributes. Thus, whether we conceive nature under the

attribute of extension, or under the attribute of thought, or

under any other attribute, we shall find the same order, or one

and the same chain of causes--that is, the same things following

in either case.

I said that God is the cause of an idea--for instance, of the

idea of a circle,--in so far as he is a thinking thing; and of a

circle, in so far as he is an extended thing, simply because the

actual being of the idea of a circle can only be perceived as a

proximate cause through another mode of thinking, and that again

through another, and so on to infinity; so that, so long as we

consider things as modes of thinking, we must explain the order

of the whole of nature, or the whole chain of causes, through the

attribute of thought only. And, in so far as we consider things

as modes of extension, we must explain the order of the whole of

nature through the attributes of extension only; and so on, in

the case of the other attributes. Wherefore of things as they

are in themselves God is really the cause, inasmuch as he

consists of infinite attributes. I cannot for the present

explain my meaning more clearly.

PROP. VIII. The ideas of particular things, or of modes, that do

not exist, must be comprehended in the infinite idea of God, in

the same way as the formal essences of particular things or modes

are contained in the attributes of God.

Proof.--This proposition is evident from the last; it is

understood more clearly from the preceding note.

Corollary.--Hence, so long as particular things do not exist,

except in so far as they are comprehended in the attributes of

God, their representations in thought or ideas do not exist,

except in so far as the infinite idea of God exists; and when

particular things are said to exist, not only in so far as they

are involved in the attributes of God, but also in so far as they

are said to continue, their ideas will also involve existence,

through which they are said to continue.

Note.--If anyone desires an example to throw more light on

this question, I shall, I fear, not be able to give him any,

which adequately explains the thing of which I here speak,

inasmuch as it is unique; however, I will endeavour to

illustrate it as far as possible. The nature of a circle is such

that if any number of straight lines intersect within it, the

rectangles formed by their segments will be equal to one another;

thus, infinite equal rectangles are contained in a circle. Yet

none of these rectangles can be said to exist, except in so far

as the circle exists; nor can the idea of any of these

rectangles be said to exist, except in so far as they are

comprehended in the idea of the circle. Let us grant that, from

this infinite number of rectangles, two only exist. The ideas of

these two not only exist, in so far as they are contained in the

idea of the circle, but also as they involve the existence of

those rectangles; wherefore they are distinguished from the

remaining ideas of the remaining rectangles.

PROP. IX. The idea of an individual thing actually existing is

caused by God, not in so far as he is infinite, but in so far as

he is considered as affected by another idea of a thing actually

existing, of which he is the cause, in so far as he is affected

by a third idea, and so on to infinity.

Proof.--The idea of an individual thing actually existing is

an individual mode of thinking, and is distinct from other modes

(by the Corollary and note to Prop. viii. of this part); thus

(by Prop. vi. of this part) it is caused by God, in so far only

as he is a thinking thing. But not (by Prop. xxviii. of Part i.)

in so far as he is a thing thinking absolutely, only in so far as

he is considered as affected by another mode of thinking; and he

is the cause of this latter, as being affected by a third, and so

on to infinity. Now, the order and connection of ideas is (by

Prop. vii. of this book) the same as the order and connection of

causes. Therefore of a given individual idea another individual

idea, or God, in so far as he is considered as modified by that

idea, is the cause; and of this second idea God is the cause, in

so far as he is affected by another idea, and so on to infinity.

Q.E.D.

Corollary.--Whatsoever takes place in the individual object of

any idea, the knowledge thereof is in God, in so far only as he

has the idea of the object.

Proof.--Whatsoever takes place in the object of any idea, its

idea is in God (by Prop. iii. of this part), not in so far as he

is infinite, but in so far as he is considered as affected by

another idea of an individual thing (by the last Prop.); but (by

Prop. vii. of this part) the order and connection of ideas is the

same as the order and connection of things. The knowledge,

therefore, of that which takes place in any individual object

will be in God, in so far only as he has the idea of that object.

Q.E.D.

PROP. X. The being of substance does not appertain to the

essence of man--in other words, substance does not constitute the

actual being[2] of man.

[2] "Forma"

Proof.--The being of substance involves necessary existence

(Part i., Prop. vii.). If, therefore, the being of substance

appertains to the essence of man, substance being granted, man

would necessarily be granted also (II. Def. ii.), and,

consequently, man would necessarily exist, which is absurd

(II. Ax. i.). Therefore, &c. Q.E.D.

Note.--This proposition may also be proved from I.v., in which

it is shown that there cannot be two substances of the same

nature; for as there may be many men, the being of substance is

not that which constitutes the actual being of man. Again, the

proposition is evident from the other properties of

substance--namely, that substance is in its nature infinite,

immutable, indivisible, &c., as anyone may see for himself.

Corollary.--Hence it follows, that the essence of man is

constituted by certain modifications of the attributes of God.

For (by the last Prop.) the being of substance does not belong to

the essence of man. That essence therefore (by i. 15) is

something which is in God, and which without God can neither be

nor be conceived, whether it be a modification (i. 25. Coroll.),

or a mode which expresses God's nature in a certain conditioned

manner.

Note.--Everyone must surely admit, that nothing can be or be

conceived without God. All men agree that God is the one and

only cause of all things, both of their essence and of their

existence; that is, God is not only the cause of things in

respect to their being made (secundum fieri), but also in respect

to their being (secundum esse).

At the same time many assert, that that, without which a

thing cannot be nor be conceived, belongs to the essence of that

thing; wherefore they believe that either the nature of God

appertains to the essence of created things, or else that created

things can be or be conceived without God; or else, as is more

probably the case, they hold inconsistent doctrines. I think the

cause for such confusion is mainly, that they do not keep to the

proper order of philosophic thinking. The nature of God, which

should be reflected on first, inasmuch as it is prior both in the

order of knowledge and the order of nature, they have taken to be

last in the order of knowledge, and have put into the first place

what they call the objects of sensation; hence, while they are

considering natural phenomena, they give no attention at all to

the divine nature, and, when afterwards they apply their mind to

the study of the divine nature, they are quite unable to bear in

mind the first hypotheses, with which they have overlaid the

knowledge of natural phenomena, inasmuch as such hypotheses are

no help towards understanding the divine nature. So that it is

hardly to be wondered at, that these persons contradict

themselves freely.

However, I pass over this point. My intention here was only

to give a reason for not saying, that that, without which a thing

cannot be or be conceived, belongs to the essence of that thing:

individual things cannot be or be conceived without God, yet God

does not appertain to their essence. I said that "I considered

as belonging to the essence of a thing that, which being given,

the thing is necessarily given also, and which being removed, the

thing is necessarily removed also; or that without which the

thing, and which itself without the thing can neither be nor be

conceived." (II. Def. ii.)

PROP. XI. The first element, which constitutes the actual being

of the human mind, is the idea of some particular thing actually

existing.

Proof.--The essence of man (by the Coroll. of the last Prop.)

is constituted by certain modes of the attributes of God, namely

(by II. Ax. ii.), by the modes of thinking, of all which (by II.

Ax. iii.) the idea is prior in nature, and, when the idea is

given, the other modes (namely, those of which the idea is prior

in nature) must be in the same individual (by the same Axiom).

Therefore an idea is the first element constituting the human

mind. But not the idea of a non--existent thing, for then (II.

viii. Coroll.) the idea itself cannot be said to exist; it must

therefore be the idea of something actually existing. But not of

an infinite thing. For an infinite thing (I. xxi., xxii.), must

always necessarily exist; this would (by II. Ax. i.) involve an

absurdity. Therefore the first element, which constitutes the

actual being of the human mind, is the idea of something actually

existing. Q.E.D.

Corollary.--Hence it follows, that the human mind is part of

the infinite intellect of God; thus when we say, that the human

mind perceives this or that, we make the assertion, that God has

this or that idea, not in so far as he is infinite, but in so far

as he is displayed through the nature of the human mind, or in so

far as he constitutes the essence of the human mind; and when we

say that God has this or that idea, not only in so far as he

constitutes the essence of the human mind, but also in so far as

he, simultaneously with the human mind, has the further idea of

another thing, we assert that the human mind perceives a thing in

part or inadequately.

Note.--Here, I doubt not, readers will come to a stand, and

will call to mind many things which will cause them to hesitate;

I therefore beg them to accompany me slowly, step by step, and

not to pronounce on my statements, till they have read to the

end.

PROP. XII. Whatsoever comes to pass in the object of the idea,

which constitutes the human mind, must be perceived by the human

mind, or there will necessarily be an idea in the human mind of

the said occurrence. That is, if the object of the idea

constituting the human mind be a body, nothing can take place in

that body without being perceived by the mind.

Proof.--Whatsoever comes to pass in the object of any idea,

the knowledge thereof is necessarily in God (II. ix. Coroll.), in

so far as he is considered as affected by the idea of the said

object, that is (II. xi.), in so far as he constitutes the mind

of anything. Therefore, whatsoever takes place in the object

constituting the idea of the human mind, the knowledge thereof is

necessarily in God, in so far as he constitutes the essence of

the human mind; that is (by II. xi. Coroll.) the knowledge of

the said thing will necessarily be in the mind, in other words

the mind perceives it.

Note.--This proposition is also evident, and is more clearly

to be understood from II. vii., which see.

PROP. XIII. The object of the idea constituting the human mind

is the body, in other words a certain mode of extension which

actually exists, and nothing else.

Proof.--If indeed the body were not the object of the human

mind, the ideas of the modifications of the body would not be in

God (II. ix. Coroll.) in virtue of his constituting our mind, but

in virtue of his constituting the mind of something else; that

is (II. xi. Coroll.) the ideas of the modifications of the body

would not be in our mind: now (by II. Ax. iv.) we do possess the

idea of the modifications of the body. Therefore the object of

the idea constituting the human mind is the body, and the body as

it actually exists (II. xi.). Further, if there were any other

object of the idea constituting the mind besides body, then, as

nothing can exist from which some effect does not follow (I.

xxxvi.) there would necessarily have to be in our mind an idea,

which would be the effect of that other object (II. xi.); but

(I. Ax. v.) there is no such idea. Wherefore the object of our

mind is the body as it exists, and nothing else. Q.E.D.

Note.--We thus comprehend, not only that the human mind is

united to the body, but also the nature of the union between mind

and body. However, no one will be able to grasp this adequately

or distinctly, unless he first has adequate knowledge of the

nature of our body. The propositions we have advanced hitherto

have been entirely general, applying not more to men than to

other individual things, all of which, though in different

degrees, are animated.[3] For of everything there is necessarily

an idea in God, of which God is the cause, in the same way as

there is an idea of the human body; thus whatever we have

asserted of the idea of the human body must necessarily also be

asserted of the idea of everything else. Still, on the other

hand, we cannot deny that ideas, like objects, differ one from

the other, one being more excellent than another and containing

more reality, just as the object of one idea is more excellent

than the object of another idea, and contains more reality.

[3] "Animata"

Wherefore, in order to determine, wherein the human mind

differs from other things, and wherein it surpasses them, it is

necessary for us to know the nature of its object, that is, of

the human body. What this nature is, I am not able here to

explain, nor is it necessary for the proof of what I advance,

that I should do so. I will only say generally, that in

proportion as any given body is more fitted than others for doing

many actions or receiving many impressions at once, so also is

the mind, of which it is the object, more fitted than others for

forming many simultaneous perceptions; and the more the actions

of the body depend on itself alone, and the fewer other bodies

concur with it in action, the more fitted is the mind of which it

is the object for distinct comprehension. We may thus recognize

the superiority of one mind over others, and may further see the

cause, why we have only a very confused knowledge of our body,

and also many kindred questions, which I will, in the following

propositions, deduce from what has been advanced. Wherefore I

have thought it worth while to explain and prove more strictly my

present statements. In order to do so, I must premise a few

propositions concerning the nature of bodies.

AXIOM I. All bodies are either in motion or at rest.

AXIOM II. Every body is moved sometimes more slowly,

sometimes more quickly.

LEMMA I. Bodies are distinguished from one another in

respect of motion and rest, quickness and slowness, and not in

respect of substance.

Proof.--The first part of this proposition is, I take it,

self--evident. That bodies are not distinguished in respect of

substance, is plain both from I. v. and I. viii. It is brought

out still more clearly from I. xv, note.

LEMMA II. All bodies agree in certain respects.

Proof.--All bodies agree in the fact, that they involve the

conception of one and the same attribute (II., Def. i.).

Further, in the fact that they may be moved less or more quickly,

and may be absolutely in motion or at rest.

LEMMA III. A body in motion or at rest must be determined to

motion or rest by another body, which other body has been

determined to motion or rest by a third body, and that third

again by a fourth, and so on to infinity.

Proof.--Bodies are individual things (II., Def. i.), which

(Lemma I.) are distinguished one from the other in respect to

motion and rest; thus (I. xxviii.) each must necessarily be

determined to motion or rest by another individual thing, namely

(II. vi.), by another body, which other body is also (Ax. i.) in

motion or at rest. And this body again can only have been set in

motion or caused to rest by being determined by a third body to

motion or rest. This third body again by a fourth, and so on to

infinity. Q.E.D.

Corollary.--Hence it follows, that a body in motion keeps in

motion, until it is determined to a state of rest by some other

body; and a body at rest remains so, until it is determined to a

state of motion by some other body. This is indeed self--evident.

For when I suppose, for instance, that a given body, A, is at

rest, and do not take into consideration other bodies in motion,

I cannot affirm anything concerning the body A, except that it is

at rest. If it afterwards comes to pass that A is in motion,

this cannot have resulted from its having been at rest, for no

other consequence could have been involved than its remaining at

rest. If, on the other hand, A be given in motion, we shall, so

long as we only consider A, be unable to affirm anything

concerning it, except that it is in motion. If A is

subsequently found to be at rest, this rest cannot be the result

of A's previous motion, for such motion can only have led to

continued motion; the state of rest therefore must have resulted

from something, which was not in A, namely, from an external

cause determining A to a state of rest.

Axiom I.--All modes, wherein one body is affected by another

body, follow simultaneously from the nature of the body affected

and the body affecting; so that one and the same body may be

moved in different modes, according to the difference in the

nature of the bodies moving it; on the other hand, different

bodies may be moved in different modes by one and the same body.

Axiom II.--When a body in motion impinges on another body at

rest, which it is unable to move, it recoils, in order to

continue its motion, and the angle made by the line of motion in

the recoil and the plane of the body at rest, whereon the moving

body has impinged, will be equal to the angle formed by the line

of motion of incidence and the same plane.

So far we have been speaking only of the most simple bodies,

which are only distinguished one from the other by motion and

rest, quickness and slowness. We now pass on to compound bodies.

Definition.--When any given bodies of the same or different

magnitude are compelled by other bodies to remain in contact, or

if they be moved at the same or different rates of speed, so that

their mutual movements should preserve among themselves a certain

fixed relation, we say that such bodies are in union, and that

together they compose one body or individual, which is

distinguished from other bodies by the fact of this union.

Axiom III.--In proportion as the parts of an individual, or a

compound body, are in contact over a greater or less superficies,

they will with greater or less difficulty admit of being moved

from their position; consequently the individual will, with

greater or less difficulty, be brought to assume another form.

Those bodies, whose parts are in contact over large superficies,

are called hard; those, whose parts are in contact over small

superficies, are called soft; those, whose parts are in motion

among one another, are called fluid.

LEMMA IV. If from a body or individual, compounded of

several bodies, certain bodies be separated, and if, at the same

time, an equal number of other bodies of the same nature take

their place, the individual will preserve its nature as before,

without any change in its actuality (forma).

Proof.--Bodies (Lemma i.) are not distinguished in respect of

substance: that which constitutes the actuality (formam) of an

individual consists (by the last Def.) in a union of bodies; but

this union, although there is a continual change of bodies, will

(by our hypothesis) be maintained; the individual, therefore,

will retain its nature as before, both in respect of substance

and in respect of mode. Q.E.D.

LEMMA V. If the parts composing an individual become greater

or less, but in such proportion, that they all preserve the same

mutual relations of motion and rest, the individual will still

preserve its original nature, and its actuality will not be

changed.

Proof.--The same as for the last Lemma.

LEMMA VI. If certain bodies composing an individual be

compelled to change the motion, which they have in one direction,

for motion in another direction, but in such a manner, that they

be able to continue their motions and their mutual communication

in the same relations as before, the individual will retain its

own nature without any change of its actuality.

Proof.--This proposition is self--evident, for the individual

is supposed to retain all that, which, in its definition, we

spoke of as its actual being.

LEMMA VII. Furthermore, the individual thus composed

preserves its nature, whether it be, as a whole, in motion or at

rest, whether it be moved in this or that direction; so long as

each part retains its motion, and preserves its communication

with other parts as before.

Proof.--This proposition is evident from the definition of an

individual prefixed to Lemma iv.

Note.--We thus see, how a composite individual may be affected

in many different ways, and preserve its nature notwithstanding.

Thus far we have conceived an individual as composed of bodies

only distinguished one from the other in respect of motion and

rest, speed and slowness; that is, of bodies of the most simple

character. If, however, we now conceive another individual

composed of several individuals of diverse natures, we shall find

that the number of ways in which it can be affected, without

losing its nature, will be greatly multiplied. Each of its parts

would consist of several bodies, and therefore (by Lemma vi.)

each part would admit, without change to its nature, of quicker

or slower motion, and would consequently be able to transmit its

motions more quickly or more slowly to the remaining parts. If

we further conceive a third kind of individuals composed of

individuals of this second kind, we shall find that they may be

affected in a still greater number of ways without changing their

actuality. We may easily proceed thus to infinity, and conceive

the whole of nature as one individual, whose parts, that is, all

bodies, vary in infinite ways, without any change in the

individual as a whole. I should feel bound to explain and

demonstrate this point at more length, if I were writing a

special treatise on body. But I have already said that such is

not my object; I have only touched on the question, because it

enables me to prove easily that which I have in view.

POSTULATES

I. The human body is composed of a number of individual

parts, of diverse nature, each one of which is in itself

extremely complex.

II. Of the individual parts composing the human body some

are fluid, some soft, some hard.

III. The individual parts composing the human body, and

consequently the human body itself, are affected in a variety of

ways by external bodies.

IV. The human body stands in need for its preservation of a

number of other bodies, by which it is continually, so to speak,

regenerated.

V. When the fluid part of the human body is determined by an

external body to impinge often on another soft part, it changes

the surface of the latter, and, as it were, leaves the impression

thereupon of the external body which impels it.

VI. The human body can move external bodies, and arrange

them in a variety of ways.

PROP. XIV. The human mind is capable of perceiving a great

number of things, and is so in proportion as its body is capable

of receiving a great number of impressions.

Proof.--The human body (by Post. iii. and vi.) is affected in

very many ways by external bodies, and is capable in very many

ways of affecting external bodies. But (II. xii.) the human

mind must perceive all that takes place in the human body; the

human mind is, therefore, capable of perceiving a great number of

things, and is so in proportion, &c. Q.E.D.

PROP. XV. The idea, which constitutes the actual being of the

human mind, is not simple, but compounded of a great number of

ideas.

Proof.--The idea constituting the actual being of the human

mind is the idea of the body (II. xiii.), which (Post. i.) is

composed of a great number of complex individual parts. But

there is necessarily in God the idea of each individual part

whereof the body is composed (II. viii. Coroll.); therefore

(II. vii.), the idea of the human body is composed of these

numerous ideas of its component parts. Q.E.D.

PROP. XVI. The idea of every mode, in which the human body is

affected by external bodies, must involve the nature of the human

body, and also the nature of the external body.

Proof.--All the modes, in which any given body is affected,

follow from the nature of the body affected, and also from the

nature of the affecting body (by Ax. i., after the Coroll. of

Lemma iii.), wherefore their idea also necessarily (by I. Ax.

iv.) involves the nature of both bodies; therefore, the idea of

every mode, in which the human body is affected by external

bodies, involves the nature of the human body and of the external

body. Q.E.D.

Corollary I.--Hence it follows, first, that the human mind

perceives the nature of a variety of bodies, together with the

nature of its own.

Corollary II.--It follows, secondly, that the ideas, which we

have of external bodies, indicate rather the constitution of our

own body than the nature of external bodies. I have amply

illustrated this in the Appendix to Part I.

PROP. XVII. If the human body is affected in a manner which

involves the nature of any external body, the human mind will

regard the said external body as actually existing, or as present

to itself, until the human body be affected in such a way, as to

exclude the existence or the presence of the said external body.

Proof.--This proposition is self--evident, for so long as the

human body continues to be thus affected, so long will the human

mind (II. xii.) regard this modification of the body--that is (by

the last Prop.), it will have the idea of the mode as actually

existing, and this idea involves the nature of the external body.

In other words, it will have the idea which does not exclude, but

postulates the existence or presence of the nature of the

external body; therefore the mind (by II. xvi., Coroll. i.) will

regard the external body as actually existing, until it is

affected, &c. Q.E.D.

Corollary.--The mind is able to regard as present external

bodies, by which the human body has once been affected, even

though they be no longer in existence or present.

Proof.--When external bodies determine the fluid parts of the

human body, so that they often impinge on the softer parts, they

change the surface of the last named (Post. v.); hence (Ax. ii.,

after the Coroll. of Lemma iii.) they are refracted therefrom in

a different manner from that which they followed before such

change; and, further, when afterwards they impinge on the new

surfaces by their own spontaneous movement, they will be

refracted in the same manner, as though they had been impelled

towards those surfaces by external bodies; consequently, they

will, while they continue to be thus refracted, affect the human

body in the same manner, whereof the mind (II. xii.) will again

take cognizance--that is (II. xvii.), the mind will again regard

the external body as present, and will do so, as often as the

fluid parts of the human body impinge on the aforesaid surfaces

by their own spontaneous motion. Wherefore, although the

external bodies, by which the human body has once been affected,

be no longer in existence, the mind will nevertheless regard them

as present, as often as this action of the body is repeated.

Q.E.D.

Note.--We thus see how it comes about, as is often the case,

that we regard as present many things which are not. It is

possible that the same result may be brought about by other

causes; but I think it suffices for me here to have indicated

one possible explanation, just as well as if I had pointed out

the true cause. Indeed, I do not think I am very far from the

truth, for all my assumptions are based on postulates, which

rest, almost without exception, on experience, that cannot be

controverted by those who have shown, as we have, that the human

body, as we feel it, exists (Coroll. after II. xiii.).

Furthermore (II. vii. Coroll., II. xvi. Coroll. ii.), we clearly

understand what is the difference between the idea, say, of

Peter, which constitutes the essence of Peter's mind, and the

idea of the said Peter, which is in another man, say, Paul. The

former directly answers to the essence of Peter's own body, and

only implies existence so long as Peter exists; the latter

indicates rather the disposition of Paul's body than the nature

of Peter, and, therefore, while this disposition of Paul's body

lasts, Paul's mind will regard Peter as present to itself, even

though he no longer exists. Further, to retain the usual

phraseology, the modifications of the human body, of which the

ideas represent external bodies as present to us, we will call

the images of things, though they do not recall the figure of

things. When the mind regards bodies in this fashion, we say

that it imagines. I will here draw attention to the fact, in

order to indicate where error lies, that the imaginations of the

mind, looked at in themselves, do not contain error. The mind

does not err in the mere act of imagining, but only in so far as

it is regarded as being without the idea, which excludes the

existence of such things as it imagines to be present to it. If

the mind, while imagining non--existent things as present to it,

is at the same time conscious that they do not really exist, this

power of imagination must be set down to the efficacy of its

nature, and not to a fault, especially if this faculty of

imagination depend solely on its own nature--that is (I. Def.

vii.), if this faculty of imagination be free.

PROP. XVIII. If the human body has once been affected by two or

more bodies at the same time, when the mind afterwards imagines

any of them, it will straightway remember the others also.

Proof.--The mind (II. xvii. Coroll.) imagines any given body,

because the human body is affected and disposed by the

impressions from an external body, in the same manner as it is

affected when certain of its parts are acted on by the said

external body; but (by our hypothesis) the body was then so

disposed, that the mind imagined two bodies at once; therefore,

it will also in the second case imagine two bodies at once, and

the mind, when it imagines one, will straightway remember the

other. Q.E.D.

Note.--We now clearly see what Memory is. It is simply a

certain association of ideas involving the nature of things

outside the human body, which association arises in the mind

according to the order and association of the modifications

(affectiones) of the human body. I say, first, it is an

association of those ideas only, which involve the nature of

things outside the human body: not of ideas which answer to the

nature of the said things: ideas of the modifications of the

human body are, strictly speaking (II. xvi.), those which involve

the nature both of the human body and of external bodies. I say,

secondly, that this association arises according to the order and

association of the modifications of the human body, in order to

distinguish it from that association of ideas, which arises from

the order of the intellect, whereby the mind perceives things

through their primary causes, and which is in all men the same.

And hence we can further clearly understand, why the mind from

the thought of one thing, should straightway arrive at the

thought of another thing, which has no similarity with the first;

for instance, from the thought of the word pomum (an apple), a

Roman would straightway arrive at the thought of the fruit apple,

which has no similitude with the articulate sound in question,

nor anything in common with it, except that the body of the man

has often been affected by these two things; that is, that the

man has often heard the word pomum, while he was looking at the

fruit; similarly every man will go on from one thought to

another, according as his habit has ordered the images of things

in his body. For a soldier, for instance, when he sees the

tracks of a horse in sand, will at once pass from the thought of

a horse to the thought of a horseman, and thence to the thought

of war, &c.; while a countryman will proceed from the thought of

a horse to the thought of a plough, a field, &c. Thus every man

will follow this or that train of thought, according as he has

been in the habit of conjoining and associating the mental images

of things in this or that manner.

PROP. XIX. The human mind has no knowledge of the body, and does

not know it to exist, save through the ideas of the modifications

whereby the body is affected.

Proof.--The human mind is the very idea or knowledge of the

human body (II. xiii.), which (II. ix.) is in God, in so far as

he is regarded as affected by another idea of a particular thing

actually existing: or, inasmuch as (Post. iv.) the human body

stands in need of very many bodies whereby it is, as it were,

continually regenerated; and the order and connection of ideas

is the same as the order and connection of causes (II. vii.);

this idea will therefore be in God, in so far as he is regarded

as affected by the ideas of very many particular things. Thus

God has the idea of the human body, or knows the human body, in

so far as he is affected by very many other ideas, and not in so

far as he constitutes the nature of the human mind; that is (by

II. xi. Coroll.), the human mind does not know the human body.

But the ideas of the modifications of body are in God, in so far

as he constitutes the nature of the human mind, or the human

mind perceives those modifications (II. xii.), and consequently

(II. xvi.) the human body itself, and as actually existing;

therefore the mind perceives thus far only the human body.

Q.E.D.

PROP. XX. The idea or knowledge of the human mind is also in

God, following in God in the same manner, and being referred to

God in the same manner, as the idea or knowledge of the human

body.

Proof.--Thought is an attribute of God (II. i.); therefore

(II. iii.) there must necessarily be in God the idea both of

thought itself and of all its modifications, consequently also of

the human mind (II. xi.). Further, this idea or knowledge of the

mind does not follow from God, in so far as he is infinite, but

in so far as he is affected by another idea of an individual

thing (II. ix.). But (II. vii.) the order and connection of

ideas is the same as the order and connection of causes;

therefore this idea or knowledge of the mind is in God and is

referred to God, in the same manner as the idea or knowledge of

the body. Q.E.D.

PROP. XXI. This idea of the mind is united to the mind in the

same way as the mind is united to the body.

Proof.--That the mind is united to the body we have shown from

the fact, that the body is the object of the mind (II. xii. and

xiii.); and so for the same reason the idea of the mind must be

united with its object, that is, with the mind in the same manner

as the mind is united to the body. Q.E.D.

Note.--This proposition is comprehended much more clearly from

what we have said in the note to II. vii. We there showed that

the idea of body and body, that is, mind and body (II. xiii.),

are one and the same individual conceived now under the attribute

of thought, now under the attribute of extension; wherefore the

idea of the mind and the mind itself are one and the same thing,

which is conceived under one and the same attribute, namely,

thought. The idea of the mind, I repeat, and the mind itself are

in God by the same necessity and follow from him from the same

power of thinking. Strictly speaking, the idea of the mind, that

is, the idea of an idea, is nothing but the distinctive quality

(forma) of the idea in so far as it is conceived as a mode of

thought without reference to the object; if a man knows

anything, he, by that very fact, knows that he knows it, and at

the same time knows that he knows that he knows it, and so on to

infinity. But I will treat of this hereafter.

PROP. XXII. The human mind perceives not only the modifications

of the body, but also the ideas of such modifications.

Proof.--The ideas of the ideas of modifications follow in God

in the same manner, and are referred to God in the same manner,

as the ideas of the said modifications. This is proved in the

same way as II. xx. But the ideas of the modifications of the

body are in the human mind (II. xii.), that is, in God, in so far

as he constitutes the essence of the human mind; therefore the

ideas of these ideas will be in God, in so far as he has the

knowledge or idea of the human mind, that is (II. xxi.), they

will be in the human mind itself, which therefore perceives not

only the modifications of the body, but also the ideas of such

modifications. Q.E.D.

PROP. XXIII. The mind does not know itself, except in so far as

it perceives the ideas of the modifications of the body.

Proof.--The idea or knowledge of the mind (II. xx.) follows in

God in the same manner, and is referred to God in the same

manner, as the idea or knowledge of the body. But since (II.

xix.) the human mind does not know the human body itself, that is

(II. xi. Coroll.), since the knowledge of the human body is not

referred to God, in so far as he constitutes the nature of the

human mind; therefore, neither is the knowledge of the mind

referred to God, in so far as he constitutes the essence of the

human mind; therefore (by the same Coroll. II. xi.), the human

mind thus far has no knowledge of itself. Further the ideas of

the modifications, whereby the body is affected, involve the

nature of the human body itself (II. xvi.), that is (II. xiii.),

they agree with the nature of the mind; wherefore the knowledge

of these ideas necessarily involves knowledge of the mind; but

(by the last Prop.) the knowledge of these ideas is in the human

mind itself; wherefore the human mind thus far only has

knowledge of itself. Q.E.D.

PROP. XXIV. The human mind does not involve an adequate

knowledge of the parts composing the human body.

Proof.--The parts composing the human body do not belong to

the essence of that body, except in so far as they communicate

their motions to one another in a certain fixed relation (Def.

after Lemma iii.), not in so far as they can be regarded as

individuals without relation to the human body. The parts of the

human body are highly complex individuals (Post. i.), whose

parts (Lemma iv.) can be separated from the human body without in

any way destroying the nature and distinctive quality of the

latter, and they can communicate their motions (Ax. i., after

Lemma iii.) to other bodies in another relation; therefore (II.

iii.) the idea or knowledge of each part will be in God,

inasmuch (II. ix.) as he is regarded as affected by another idea

of a particular thing, which particular thing is prior in the

order of nature to the aforesaid part (II. vii.). We may affirm

the same thing of each part of each individual composing the

human body; therefore, the knowledge of each part composing the

human body is in God, in so far as he is affected by very many

ideas of things, and not in so far as he has the idea of the

human body only, in other words, the idea which constitutes the

nature of the human mind (II. xiii); therefore (II. xi.

Coroll.), the human mind does not involve an adequate knowledge

of the human body. Q.E.D.

PROP. XXV. The idea of each modification of the human body does

not involve an adequate knowledge of the external body.

Proof.--We have shown that the idea of a modification of the

human body involves the nature of an external body, in so far as

that external body conditions the human body in a given manner.

But, in so far as the external body is an individual, which has

no reference to the human body, the knowledge or idea thereof is

in God (II. ix.), in so far as God is regarded as affected by the

idea of a further thing, which (II. vii.) is naturally prior to

the said external body. Wherefore an adequate knowledge of the

external body is not in God, in so far as he has the idea of the

modification of the human body; in other words, the idea of the

modification of the human body does not involve an adequate

knowledge of the external body. Q.E.D.

PROP. XXVI. The human mind does not perceive any external body

as actually existing, except through the ideas of the

modifications of its own body.

Proof.--If the human body is in no way affected by a given

external body, then (II. vii.) neither is the idea of the human

body, in other words, the human mind, affected in any way by the

idea of the existence of the said external body, nor does it in

any manner perceive its existence. But, in so far as the human

body is affected in any way by a given external body, thus far

(II. xvi. and Coroll.) it perceives that external body. Q.E.D.

Corollary.--In so far as the human mind imagines an external

body, it has not an adequate knowledge thereof.

Proof.--When the human mind regards external bodies through

the ideas of the modifications of its own body, we say that it

imagines (see II. xvii. note); now the mind can only imagine

external bodies as actually existing. Therefore (by II. xxv.),

in so far as the mind imagines external bodies, it has not an

adequate knowledge of them. Q.E.D.

PROP. XXVII. The idea of each modification of the human body

does not involve an adequate knowledge of the human body itself.

Proof.--Every idea of a modification of the human body

involves the nature of the human body, in so far as the human

body is regarded as affected in a given manner (II. xvi.). But,

inasmuch as the human body is an individual which may be affected

in many other ways, the idea of the said modification, &c.

Q.E.D.

PROP. XXVIII. The ideas of the modifications of the human body,

in so far as they have reference only to the human mind, are not

clear and distinct, but confused.

Proof.--The ideas of the modifications of the human body

involve the nature both of the human body and of external bodies

(II. xvi.); they must involve the nature not only of the human

body but also of its parts; for the modifications are modes

(Post. iii.), whereby the parts of the human body, and,

consequently, the human body as a whole are affected. But (by

II. xxiv., xxv.) the adequate knowledge of external bodies, as

also of the parts composing the human body, is not in God, in so

far as he is regarded as affected by the human mind, but in so

far as he is regarded as affected by other ideas. These ideas of

modifications, in so far as they are referred to the human mind

alone, are as consequences without premisses, in other words,

confused ideas. Q.E.D.

Note.--The idea which constitutes the nature of the human mind

is, in the same manner, proved not to be, when considered in

itself alone, clear and distinct; as also is the case with the

idea of the human mind, and the ideas of the ideas of the

modifications of the human body, in so far as they are referred

to the mind only, as everyone may easily see.

PROP. XXIX. The idea of the idea of each modification of the

human body does not involve an adequate knowledge of the human

mind.

Proof.--The idea of a modification of the human body (II.

xxvii.) does not involve an adequate knowledge of the said body,

in other words, does not adequately express its nature; that is

(II. xiii.) it does not agree with the nature of the mind

adequately; therefore (I. Ax. vi) the idea of this idea does not

adequately express the nature of the human mind, or does not

involve an adequate knowledge thereof.

Corollary.--Hence it follows that the human mind, when it

perceives things after the common order of nature, has not an

adequate but only a confused and fragmentary knowledge of itself,

of its own body, and of external bodies. For the mind does not

know itself, except in so far as it perceives the ideas of the

modifications of body (II. xxiii.). It only perceives its own

body (II. xix.) through the ideas of the modifications, and only

perceives external bodies through the same means; thus, in so

far as it has such ideas of modification, it has not an adequate

knowledge of itself (II. xxix.), nor of its own body (II.

xxvii.), nor of external bodies (II. xxv.), but only a

fragmentary and confused knowledge thereof (II. xxviii. and

note). Q.E.D.

Note.--I say expressly, that the mind has not an adequate but

only a confused knowledge of itself, its own body, and of

external bodies, whenever it perceives things after the common

order of nature; that is, whenever it is determined from

without, namely, by the fortuitous play of circumstance, to

regard this or that; not at such times as it is determined from

within, that is, by the fact of regarding several things at once,

to understand their points of agreement, difference, and

contrast. Whenever it is determined in anywise from within, it

regards things clearly and distinctly, as I will show below.

PROP. XXX. We can only have a very inadequate knowledge of the

duration of our body.

Proof.--The duration of our body does not depend on its

essence (II. Ax. i.), nor on the absolute nature of God (I.

xxi.). But (I. xxviii.) it is conditioned to exist and operate

by causes, which in their turn are conditioned to exist and

operate in a fixed and definite relation by other causes, these

last again being conditioned by others, and so on to infinity.

The duration of our body therefore depends on the common order of

nature, or the constitution of things. Now, however a thing may

be constituted, the adequate knowledge of that thing is in God,

in so far as he has the ideas of all things, and not in so far as

he has the idea of the human body only. (II. ix. Coroll.)

Wherefore the knowledge of the duration of our body is in God

very inadequate, in so far as he is only regarded as constituting

the nature of the human mind; that is (II. xi. Coroll.), this

knowledge is very inadequate to our mind. Q.E.D.

PROP. XXXI. We can only have a very inadequate knowledge of the

duration of particular things external to ourselves.

Proof.--Every particular thing, like the human body, must be

conditioned by another particular thing to exist and operate in a

fixed and definite relation; this other particular thing must

likewise be conditioned by a third, and so on to infinity. (I.

xxviii.) As we have shown in the foregoing proposition, from

this common property of particular things, we have only a very

inadequate knowledge of the duration of our body; we must draw a

similar conclusion with regard to the duration of particular

things, namely, that we can only have a very inadequate knowledge

of the duration thereof. Q.E.D.

Corollary.--Hence it follows that all particular things are

contingent and perishable. For we can have no adequate idea of

their duration (by the last Prop.), and this is what we must

understand by the contingency and perishableness of things. (I.

xxxiii., Note i.) For (I. xxix.), except in this sense, nothing

is contingent.

PROP. XXXII. All ideas, in so far as they are referred to God,

are true.

Proof.--All ideas which are in God agree in every respect with

their objects (II. vii. Coroll.), therefore (I. Ax. vi.) they are

all true. Q.E.D.

PROP. XXXIII. There is nothing positive in ideas, which causes

them to be called false.

Proof.--If this be denied, conceive, if possible, a positive

mode of thinking, which should constitute the distinctive quality

of falsehood. Such a mode of thinking cannot be in God (II.

xxxii.); external to God it cannot be or be conceived (I. xv.).

Therefore there is nothing positive in ideas which causes them to

be called false. Q.E.D.

PROP. XXXIV. Every idea, which in us is absolute or adequate and

perfect, is true.

Proof.--When we say that an idea in us is adequate and

perfect, we say, in other words (II. xi. Coroll.), that the idea

is adequate and perfect in God, in so far as he constitutes the

essence of our mind; consequently (II. xxxii.), we say that such

an idea is true. Q.E.D.

PROP. XXXV. Falsity consists in the privation of knowledge,

which inadequate, fragmentary, or confused ideas involve.

Proof.--There is nothing positive in ideas, which causes them

to be called false (II. xxxiii.); but falsity cannot consist in

simple privation (for minds, not bodies, are said to err and to

be mistaken), neither can it consist in absolute ignorance, for

ignorance and error are not identical; wherefore it consists in

the privation of knowledge, which inadequate, fragmentary, or

confused ideas involve. Q.E.D.

Note.--In the note to II. xvii. I explained how error consists

in the privation of knowledge, but in order to throw more light

on the subject I will give an example. For instance, men are

mistaken in thinking themselves free; their opinion is made up

of consciousness of their own actions, and ignorance of the

causes by which they are conditioned. Their idea of freedom,

therefore, is simply their ignorance of any cause for their

actions. As for their saying that human actions depend on the

will, this is a mere phrase without any idea to correspond

thereto. What the will is, and how it moves the body, they none

of them know; those who boast of such knowledge, and feign

dwellings and habitations for the soul, are wont to provoke

either laughter or disgust. So, again, when we look at the sun,

we imagine that it is distant from us about two hundred feet;

this error does not lie solely in this fancy, but in the fact

that, while we thus imagine, we do not know the sun's true

distance or the cause of the fancy. For although we afterwards

learn, that the sun is distant from us more than six hundred of

the earth's diameters, we none the less shall fancy it to be near;

for we do not imagine the sun as near us, because we are

ignorant of its true distance, but because the modification of

our body involves the essence of the sun, in so far as our said

body is affected thereby.

PROP. XXXVI. Inadequate and confused ideas follow by the same

necessity, as adequate or clear and distinct ideas.

Proof.--All ideas are in God (I. xv.), and in so far as they

are referred to God are true (II. xxxii.) and (II. vii. Coroll.)

adequate; therefore there are no ideas confused or inadequate,

except in respect to a particular mind (cf. II. xxiv. and

xxviii.); therefore all ideas, whether adequate or inadequate,

follow by the same necessity (II. vi.). Q.E.D.

PROP. XXXVII. That which is common to all (cf. Lemma II.,

above), and which is equally in a part and in the whole, does not

constitute the essence of any particular thing.

Proof.--If this be denied, conceive, if possible, that it

constitutes the essence of some particular thing; for instance,

the essence of B. Then (II. Def. ii.) it cannot without B either

exist or be conceived; but this is against our hypothesis.

Therefore it does not appertain to B's essence, nor does it

constitute the essence of any particular thing. Q.E.D.

PROP. XXXVIII. Those things, which are common to all, and which

are equally in a part and in the whole, cannot be conceived

except adequately.

Proof.--Let A be something, which is common to all bodies, and

which is equally present in the part of any given body and in the

whole. I say A cannot be conceived except adequately. For the

idea thereof in God will necessarily be adequate (II. vii.

Coroll.), both in so far as God has the idea of the human body,

and also in so far as he has the idea of the modifications of the

human body, which (II. xvi., xxv., xxvii.) involve in part the

nature of the human body and the nature of external bodies; that

is (II. xii., xiii.), the idea in God will necessarily be

adequate, both in so far as he constitutes the human mind, and in

so far as he has the ideas, which are in the human mind.

Therefore the mind (II. xi. Coroll.) necessarily perceives A

adequately, and has this adequate perception, both in so far as

it perceives itself, and in so far as it perceives its own or any

external body, nor can A be conceived in any other manner.

Q.E.D.

Corollary--Hence it follows that there are certain ideas or

notions common to all men; for (by Lemma ii.) all bodies agree

in certain respects, which (by the foregoing Prop.) must be

adequately or clearly and distinctly perceived by all.

PROP. XXXIX. That, which is common to and a property of the

human body and such other bodies as are wont to affect the human

body, and which is present equally in each part of either, or in

the whole, will be represented by an adequate idea in the mind.

Proof.--If A be that, which is common to and a property of the

human body and external bodies, and equally present in the human

body and in the said external bodies, in each part of each

external body and in the whole, there will be an adequate idea of

A in God (II. vii. Coroll.), both in so far as he has the idea of

the human body, and in so far as he has the ideas of the given

external bodies. Let it now be granted, that the human body is

affected by an external body through that, which it has in common

therewith, namely, A; the idea of this modification will involve

the property A (II. xvi.), and therefore (II. vii. Coroll.) the

idea of this modification, in so far as it involves the property

A, will be adequate in God, in so far as God is affected by the

idea of the human body; that is (II. xiii.), in so far as he

constitutes the nature of the human mind; therefore (II. xi.

Coroll.) this idea is also adequate in the human mind. Q.E.D.

Corollary.--Hence it follows that the mind is fitted to

perceive adequately more things, in proportion as its body has