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

the “biography”

to which the sensation belongs as the set of particulars that are

earlier or later than, or simultaneous with, the given sensation.

Moreover, the very same definitions can be applied to particulars

which are not sensations. They are actually required for the

theory of relativity, if we are to give a philosophical

explanation of what is meant by “local time” in that theory The

relations of simultaneity and succession are known to us in our

own experience; they may be analysable, but that does not affect

their suitability for defining perspectives and biographies. Such

time-relations as can be constructed between events in different

biographies are of a different kind: they are not experienced,

and are merely logical, being designed to afford convenient ways

of stating the correlations between different biographies.

 

It is not only by time-relations that the parts of one biography

are collected together in the case of living beings. In this case

there are the mnemic phenomena which constitute the unity of one

“experience,” and transform mere occurrences into “experiences.”

I have already dwelt upon the importance of mnemic phenomena for

psychology, and shall not enlarge upon them now, beyond observing

that they are what transforms a biography (in our technical

sense) into a life. It is they that give the continuity of a

“person” or a “mind.” But there is no reason to suppose that

mnemic phenomena are associated with biographies except in the

case of animals and plants.

 

Our twofold classification of particulars gives rise to the

dualism of body and biography in regard to everything in the

universe, and not only in regard to living things. This arises as

follows. Every particular of the sort considered by physics is a

member of two groups (1) The group of particulars constituting

the other aspects of the same physical object; (2) The group of

particulars that have direct time-relations to the given

particular.

 

Each of these is associated with a place. When I look at a star,

my sensation is (1) A member of the group of particulars which is

the star, and which is associated with the place where the star

is; (2) A member of the group of particulars which is my

biography, and which is associated with the place where I am.*

 

*I have explained elsewhere the manner in which space is

constructed on this theory, and in which the position of a

perspective is brought into relation with the position of a

physical object (“Our Knowledge of the External World,” Lecture

III, pp. 90, 91).

 

The result is that every particular of the kind relevant to

physics is associated with TWO places; e.g. my sensation of the

star is associated with the place where I am and with the place

where the star is. This dualism has nothing to do with any “mind”

that I may be supposed to possess; it exists in exactly the same

sense if I am replaced by a photographic plate. We may call the

two places the active and passive places respectively.* Thus in

the case of a perception or photograph of a star, the active

place is the place where the star is, while the passive place is

the place where the percipient or photographic plate is.

 

* I use these as mere names; I do not want to introduce any

notion of “activity.”

 

We can thus, without departing from physics, collect together all

the particulars actively at a given place, or all the particulars

passively at a given place. In our own case, the one group is our

body (or our brain), while the other is our mind, in so far as it

consists of perceptions. In the case of the photographic plate,

the first group is the plate as dealt with by physics, the second

the aspect of the heavens which it photographs. (For the sake of

schematic simplicity, I am ignoring various complications

connected with time, which require some tedious but perfectly

feasible elaborations.) Thus what may be called subjectivity in

the point of view is not a distinctive peculiarity of mind: it is

present just as much in the photographic plate. And the

photographic plate has its biography as well as its “matter.” But

this biography is an affair of physics, and has none of the

peculiar characteristics by which “mental” phenomena are

distinguished, with the sole exception of subjectivity.

 

Adhering, for the moment, to the standpoint of physics, we may

define a “perception” of an object as the appearance of the

object from a place where there is a brain (or, in lower animals,

some suitable nervous structure), with sense-organs and nerves

forming part of the intervening medium. Such appearances of

objects are distinguished from appearances in other places by

certain peculiarities, namely

 

(1) They give rise to mnemic phenomena;

 

(2) They are themselves affected by mnemic phenomena.

 

That is to say, they may be remembered and associated or

influence our habits, or give rise to images, etc., and they are

themselves different from what they would have been if our past

experience had been different—for example, the effect of a

spoken sentence upon the hearer depends upon whether the hearer

knows the language or not, which is a question of past

experience. It is these two characteristics, both connected with

mnemic phenomena, that distinguish perceptions from the

appearances of objects in places where there is no living being.

 

Theoretically, though often not practically, we can, in our

perception of an object, separate the part which is due to past

experience from the part which proceeds without mnemic influences

out of the character of the object. We may define as “sensation”

that part which proceeds in this way, while the remainder, which

is a mnemic phenomenon, will have to be added to the sensation to

make up what is called the “perception.” According to this

definition, the sensation is a theoretical core in the actual

experience; the actual experience is the perception. It is

obvious that there are grave difficulties in carrying out these

definitions, but we will not linger over them. We have to pass,

as soon as we can, from the physical standpoint, which we have

been hitherto adopting, to the standpoint of psychology, in which

we make more use of introspection in the first of the three

senses discussed in the preceding lecture.

 

But before making the transition, there are two points which must

be made clear. First: Everything outside my own personal

biography is outside my experience; therefore if anything can be

known by me outside my biography, it can only be known in one of

two ways

 

(1) By inference from things within my biography, or

 

(2) By some a priori principle independent of experience.

 

I do not myself believe that anything approaching certainty is to

be attained by either of these methods, and therefore whatever

lies outside my personal biography must be regarded,

theoretically, as hypothesis. The theoretical argument for

adopting the hypothesis is that it simplifies the statement of

the laws according to which events happen in our experience. But

there is no very good ground for supposing that a simple law is

more likely to be true than a complicated law, though there is

good ground for assuming a simple law in scientific practice, as

a working hypothesis, if it explains the facts as well as another

which is less simple. Belief in the existence of things outside

my own biography exists antecedently to evidence, and can only be

destroyed, if at all, by a long course of philosophic doubt. For

purposes of science, it is justified practically by the

simplification which it introduces into the laws of physics. But

from the standpoint of theoretical logic it must be regarded as a

prejudice, not as a well-grounded theory. With this proviso, I

propose to continue yielding to the prejudice.

 

The second point concerns the relating of our point of view to

that which regards sensations as caused by stimuli external to

the nervous system (or at least to the brain), and distinguishes

images as “centrally excited,” i.e. due to causes in the brain

which cannot be traced back to anything affecting the

sense-organs. It is clear that, if our analysis of physical

objects has been valid, this way of defining sensations needs

reinterpretation. It is also clear that we must be able to find

such a new interpretation if our theory is to be admissible.

 

To make the matter clear, we will take the simplest possible

illustration. Consider a certain star, and suppose for the moment

that its size is negligible. That is to say, we will regard it

as, for practical purposes, a luminous point. Let us further

suppose that it exists only for a very brief time, say a second.

Then, according to physics, what happens is that a spherical wave

of light travels outward from the star through space, just as,

when you drop a stone into a stagnant pond, ripples travel

outward from the place where the stone hit the water. The wave of

light travels with a certain very nearly constant velocity,

roughly 300,000 kilometres per second. This velocity may be

ascertained by sending a flash of light to a mirror, and

observing how long it takes before the reflected flash reaches

you, just as the velocity of sound may be ascertained by means of

an echo.

 

What it is that happens when a wave of light reaches a given

place we cannot tell, except in the sole case when the place in

question is a brain connected with an eye which is turned in the

right direction. In this one very special case we know what

happens: we have the sensation called “seeing the star.” In all

other cases, though we know (more or less hypothetically) some of

the correlations and abstract properties of the appearance of the

star, we do not know the appearance itself. Now you may, for the

sake of illustration, compare the different appearances of the

star to the conjugation of a Greek verb, except that the number

of its parts is really infinite, and not only apparently so to

the despairing schoolboy. In vacuo, the parts are regular, and

can be derived from the (imaginary) root according to the laws of

grammar, i.e. of perspective. The star being situated in empty

space, it may be defined, for purposes of physics, as consisting

of all those appearances which it presents in vacuo, together

with those which, according to the laws of perspective, it would

present elsewhere if its appearances elsewhere were regular. This

is merely the adaptation of the definition of matter which I gave

in an earlier lecture. The appearance of a star at a certain

place, if it is regular, does not require any cause or

explanation beyond the existence of the star. Every regular

appearance is an actual member of the system which is the star,

and its causation is entirely internal to that system. We may

express this by saying that a regular appearance is due to the

star alone, and is actually part of the star, in the sense in

which a man is part of the human race.

 

But presently the light of the star reaches our atmosphere. It

begins to be refracted, and dimmed by mist, and its velocity is

slightly diminished. At last it reaches a human eye, where a

complicated process takes place, ending in a sensation which

gives us our grounds for believing in all that has gone before.

Now, the irregular appearances of the star are not, strictly

speaking, members of the system which is the star, according to

our definition of matter. The irregular appearances, however, are

not merely irregular: they proceed according to laws which can be

stated in terms of the matter through which the light has passed

on its way. The sources of