The Analysis of Mind, Bertrand Russell [best desktop ebook reader .txt] 📗

is happening there which is specially connected with

that star. Therefore in every place at all times a vast multitude

of things must be happening, namely, at least one for every

physical object which can be seen or photographed from that

place. We can classify such happenings on either of two

principles:

 

(1) We can collect together all the happenings in one place, as

is done by photography so far as light is concerned;

 

(2) We can collect together all the happenings, in different

places, which are connected in the way that common sense regards

as being due to their emanating from one object.

 

Thus, to return to the stars, we can collect together either—

 

(1) All the appearances of different stars in a given place, or,

 

(2) All the appearances of a given star in different places.

 

But when I speak of “appearances,” I do so only for brevity: I do

not mean anything that must “appear” to somebody, but only that

happening, whatever it may be, which is connected, at the place

in question, with a given physical object—according to the old

orthodox theory, it would be a transverse vibration in the

aether. Like the different appearances of the table to a number

of simultaneous observers, the different particulars that belong

to one physical object are to be collected together by continuity

and inherent laws of correlation, not by their supposed causal

connection with an unknown assumed existent called a piece of

matter, which would be a mere unnecessary metaphysical thing in

itself. A piece of matter, according to the definition that I

propose, is, as a first approximation,* the collection of all

those correlated particulars which would normally be regarded as

its appearances or effects in different places. Some further

elaborations are desirable, but we can ignore them for the

present. I shall return to them at the end of this lecture.

 

*The exact definition of a piece of matter as a construction will

be given later.

 

According to the view that I am suggesting, a physical object or

piece of matter is the collection of all those correlated

particulars which would be regarded by common sense as its

effects or appearances in different places. On the other hand,

all the happenings in a given place represent what common sense

would regard as the appearances of a number of different objects

as viewed from that place. All the happenings in one place may be

regarded as the view of the world from that place. I shall call

the view of the world from a given place a “perspective.” A

photograph represents a perspective. On the other hand, if

photographs of the stars were taken in all points throughout

space, and in all such photographs a certain star, say Sirius,

were picked out whenever it appeared, all the different

appearances of Sirius, taken together, would represent Sirius.

For the understanding of the difference between psychology and

physics it is vital to understand these two ways of classifying

particulars, namely:

 

(1) According to the place where they occur;

 

(2) According to the system of correlated particulars in

different places to which they belong, such system being defined

as a physical object.

 

Given a system of particulars which is a physical object, I shall

define that one of the system which is in a given place (if any)

as the “appearance of that object in that place.”

 

When the appearance of an object in a given place changes, it is

found that one or other of two things occurs. The two

possibilities may be illustrated by an example. You are in a room

with a man, whom you see: you may cease to see him either by

shutting your eyes or by his going out of the room. In the first

case, his appearance to other people remains unchanged; in the

second, his appearance changes from all places. In the first

case, you say that it is not he who has changed, but your eyes;

in the second, you say that he has changed. Generalizing, we

distinguish—

 

(1) Cases in which only certain appearances of the object change,

while others, and especially appearances from places very near to

the object, do not change;

 

(2) Cases where all, or almost all, the appearances of the object

undergo a connected change.

 

In the first case, the change is attributed to the medium between

the object and the place; in the second, it is attributed to the

object itself.*

 

* The application of this distinction to motion raises

complications due to relativity, but we may ignore these for our

present purposes.

 

It is the frequency of the latter kind of change, and the

comparatively simple nature of the laws governing the

simultaneous alterations of appearances in such cases, that have

made it possible to treat a physical object as one thing, and to

overlook the fact that it is a system of particulars. When a

number of people at a theatre watch an actor, the changes in

their several perspectives are so similar and so closely

correlated that all are popularly regarded as identical with each

other and with the changes of the actor himself. So long as all

the changes in the appearances of a body are thus correlated

there is no pressing prima facie need to break up the system of

appearances, or to realize that the body in question is not

really one thing but a set of correlated particulars. It is

especially and primarily such changes that physics deals with,

i.e. it deals primarily with processes in which the unity of a

physical object need not be broken up because all its appearances

change simultaneously according to the same law—or, if not all,

at any rate all from places sufficiently near to the object, with

in creasing accuracy as we approach the object.

 

The changes in appearances of an object which are due to changes

in the intervening medium will not affect, or will affect only

very slightly, the appearances from places close to the object.

If the appearances from sufficiently neighbouring places are

either wholly un changed, or changed to a diminishing extent

which has zero for its limit, it is usually found that the

changes can be accounted for by changes in objects which are

between the object in question and the places from which its

appearance has changed appreciably. Thus physics is able to

reduce the laws of most changes with which it deals to changes in

physical objects, and to state most of its fundamental laws in

terms of matter. It is only in those cases in which the unity of

the system of appearances constituting a piece of matter has to

be broken up, that the statement of what is happening cannot be

made exclusively in terms of matter. The whole of psychology, we

shall find, is included among such cases; hence their importance

for our purposes.

 

We can now begin to understand one of the fundamental differences

between physics and psychology. Physics treats as a unit the

whole system of appearances of a piece of matter, whereas

psychology is interested in certain of these appearances

themselves. Confining ourselves for the moment to the psychology

of perceptions, we observe that perceptions are certain of the

appearances of physical objects. From the point of view that we

have been hitherto adopting, we might define them as the

appearances of objects at places from which sense-organs and the

suitable parts of the nervous system form part of the intervening

medium. Just as a photographic plate receives a different

impression of a cluster of stars when a telescope is part of the

intervening medium, so a brain receives a different impression

when an eye and an optic nerve are part of the intervening

medium. An impression due to this sort of intervening medium is

called a perception, and is interesting to psychology on its own

account, not merely as one of the set of correlated particulars

which is the physical object of which (as we say) we are having a

perception.

 

We spoke earlier of two ways of classifying particulars. One way

collects together the appearances commonly regarded as a given

object from different places; this is, broadly speaking, the way

of physics, leading to the construction of physical objects as

sets of such appearances. The other way collects together the

appearances of different objects from a given place, the result

being what we call a perspective. In the particular case where

the place concerned is a human brain, the perspective belonging

to the place consists of all the perceptions of a certain man at

a given time. Thus classification by perspectives is relevant to

psychology, and is essential in defining what we mean by one

mind.

 

I do not wish to suggest that the way in which I have been

defining perceptions is the only possible way, or even the best

way. It is the way that arose naturally out of our present topic.

But when we approach psychology from a more introspective

standpoint, we have to distinguish sensations and perceptions, if

possible, from other mental occurrences, if any. We have also to

consider the psychological effects of sensations, as opposed to

their physical causes and correlates. These problems are quite

distinct from those with which we have been concerned in the

present lecture, and I shall not deal with them until a later

stage.

 

It is clear that psychology is concerned essentially with actual

particulars, not merely with systems of particulars. In this it

differs from physics, which, broadly speaking, is concerned with

the cases in which all the particulars which make up one physical

object can be treated as a single causal unit, or rather the

particulars which are sufficiently near to the object of which

they are appearances can be so treated. The laws which physics

seeks can, broadly speaking, be stated by treating such systems

of particulars as causal units. The laws which psychology seeks

cannot be so stated, since the particulars themselves are what

interests the psychologist. This is one of the fundamental

differences between physics and psychology; and to make it clear

has been the main purpose of this lecture.

 

I will conclude with an attempt to give a more precise definition

of a piece of matter. The appearances of a piece of matter from

different places change partly according to intrinsic laws (the

laws of perspective, in the case of visual shape), partly

according to the nature of the intervening medium—fog, blue

spectacles, telescopes, microscopes, sense-organs, etc. As we

approach nearer to the object, the effect of the intervening

medium grows less. In a generalized sense, all the intrinsic laws

of change of appearance may be called “laws of perspective.”

Given any appearance of an object, we can construct

hypothetically a certain system of appearances to which the

appearance in question would belong if the laws of perspective

alone were concerned. If we construct this hypothetical system

for each appearance of the object in turn, the system

corresponding to a given appearance x will be independent of any

distortion due to the medium beyond x, and will only embody such

distortion as is due to the medium between x and the object.

Thus, as the appearance by which our hypothetical system is

defined is moved nearer and nearer to the object, the

hypothetical system of appearances defined by its means embodies

less and less of the effect of the medium. The different sets of

appearances resulting from moving x nearer and nearer to the

object will approach to a limiting set, and this limiting set

will be that system of appearances which the object would present

if the laws of perspective alone were operative and the medium

exercised no distorting effect. This limiting set of appearances

may be defined, for purposes of physics, as