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

of acquiring

experience cannot be used to define mind.*

 

* Cf. Lecture IV.

 

Very similar considerations apply to memory, if taken as the

essence of mind. A recollection is aroused by something which is

happening now, but is different from the effect which the present

occurrence would have produced if the recollected event had not

occurred. This may be accounted for by the physical effect of the

past event on the brain, making it a different instrument from

that which would have resulted from a different experience. The

causal peculiarities of memory may, therefore, have a

physiological explanation. With every special class of mental

phenomena this possibility meets us afresh. If psychology is to

be a separate science at all, we must seek a wider ground for its

separateness than any that we have been considering hitherto.

 

We have found that “consciousness” is too narrow to characterize

mental phenomena, and that mnemic causation is too wide. I come

now to a characteristic which, though difficult to define, comes

much nearer to what we require, namely subjectivity.

 

Subjectivity, as a characteristic of mental phenomena, was

considered in Lecture VII, in connection with the definition of

perception. We there decided that those particulars which

constitute the physical world can be collected into sets in two

ways, one of which makes a bundle of all those particulars that

are appearances of a given thing from different places, while the

other makes a bundle of all those particulars which are

appearances of different things from a given place. A bundle of

this latter sort, at a given time, is called a “perspective”;

taken throughout a period of time, it is called a “biography.”

Subjectivity is the characteristic of perspectives and

biographies, the characteristic of giving the view of the world

from a certain place. We saw in Lecture VII that this

characteristic involves none of the other characteristics that

are commonly associated with mental phenomena, such as

consciousness, experience and memory. We found in fact that it is

exhibited by a photographic plate, and, strictly speaking, by any

particular taken in conjunction with those which have the same

“passive” place in the sense defined in Lecture VII. The

particulars forming one perspective are connected together

primarily by simultaneity; those forming one biography, primarily

by the existence of direct time-relations between them. To these

are to be added relations derivable from the laws of perspective.

In all this we are clearly not in the region of psychology, as

commonly understood; yet we are also hardly in the region of

physics. And the definition of perspectives and biographies,

though it does not yet yield anything that would be commonly

called “mental,” is presupposed in mental phenomena, for example

in mnemic causation: the causal unit in mnemic causation, which

gives rise to Semon’s engram, is the whole of one perspective—

not of any perspective, but of a perspective in a place where

there is nervous tissue, or at any rate living tissue of some

sort. Perception also, as we saw, can only be defined in terms of

perspectives. Thus the conception of subjectivity, i.e. of the

“passive” place of a particular, though not alone sufficient to

define mind, is clearly an essential element in the definition.

 

I have maintained throughout these lectures that the data of

psychology do not differ in, their intrinsic character from the

data of physics. I have maintained that sensations are data for

psychology and physics equally, while images, which may be in

some sense exclusively psychological data, can only be

distinguished from sensations by their correlations, not by what

they are in themselves. It is now necessary, however, to examine

the notion of a “datum,” and to obtain, if possible, a definition

of this notion.

 

The notion of “data” is familiar throughout science, and is

usually treated by men of science as though it were perfectly

clear. Psychologists, on the other hand, find great difficulty in

the conception. “Data” are naturally defined in terms of theory

of knowledge: they are those propositions of which the truth is

known without demonstration, so that they may be used as

premisses in proving other propositions. Further, when a

proposition which is a datum asserts the existence of something,

we say that the something is a datum, as well as the proposition

asserting its existence. Thus those objects of whose existence we

become certain through perception are said to be data.

 

There is some difficulty in connecting this epistemological

definition of “data” with our psychological analysis of

knowledge; but until such a connection has been effected, we have

no right to use the conception “data.”

 

It is clear, in the first place, that there can be no datum apart

from a belief. A sensation which merely comes and goes is not a

datum; it only becomes a datum when it is remembered. Similarly,

in perception, we do not have a datum unless we have a JUDGMENT

of perception. In the sense in which objects (as opposed to

propositions) are data, it would seem natural to say that those

objects of which we are conscious are data. But consciousness, as

we have seen, is a complex notion, involving beliefs, as well as

mnemic phenomena such as are required for perception and memory.

It follows that no datum is theoretically indubitable, since no

belief is infallible; it follows also that every datum has a

greater or less degree of vagueness, since there is always some

vagueness in memory and the meaning of images.

 

Data are not those things of which our consciousness is earliest

in time. At every period of life, after we have become capable of

thought, some of our beliefs are obtained by inference, while

others are not. A belief may pass from either of these classes

into the other, and may therefore become, or cease to be, a

belief giving a datum. When, in what follows, I speak of data, I

do not mean the things of which we feel sure before scientific

study begins, but the things which, when a science is well

advanced, appear as affording grounds for other parts of the

science, without themselves being believed on any ground except

observation. I assume, that is to say, a trained observer, with

an analytic attention, knowing the sort of thing to look for, and

the sort of thing that will be important. What he observes is, at

the stage of science which he has reached, a datum for his

science. It is just as sophisticated and elaborate as the

theories which he bases upon it, since only trained habits and

much practice enable a man to make the kind of observation that

will be scientifically illuminating. Nevertheless, when once it

has been observed, belief in it is not based on inference and

reasoning, but merely upon its having been seen. In this way its

logical status differs from that of the theories which are proved

by its means.

 

In any science other than psychology the datum is primarily a

perception, in which only the sensational core is ultimately and

theoretically a datum, though some such accretions as turn the

sensation into a perception are practically unavoidable. But if

we postulate an ideal observer, he will be able to isolate the

sensation, and treat this alone as datum. There is, therefore, an

important sense in which we may say that, if we analyse as much

as we ought, our data, outside psychology, consist of sensations,

which include within themselves certain spatial and temporal

relations.

 

Applying this remark to physiology, we see that the nerves and

brain as physical objects are not truly data; they are to be

replaced, in the ideal structure of science, by the sensations

through which the physiologist is said to perceive them. The

passage from these sensations to nerves and brain as physical

objects belongs really to the initial stage in the theory of

physics, and ought to be placed in the reasoned part, not in the

part supposed to be observed. To say we see the nerves is like

saying we hear the nightingale; both are convenient but

inaccurate expressions. We hear a sound which we believe to be

causally connected with the nightingale, and we see a sight which

we believe to be causally connected with a nerve. But in each

case it is only the sensation that ought, in strictness, to be

called a datum. Now, sensations are certainly among the data of

psychology. Therefore all the data of the physical sciences are

also psychological data. It remains to inquire whether all the

data of psychology are also data of physical science, and

especially of physiology.

 

If we have been right in our analysis of mind, the ultimate data

of psychology are only sensations and images and their relations.

Beliefs, desires, volitions, and so on, appeared to us to be

complex phenomena consisting of sensations and images variously

interrelated. Thus (apart from certain relations) the occurrences

which seem most distinctively mental, and furthest removed from

physics, are, like physical objects, constructed or inferred, not

part of the original stock of data in the perfected science. From

both ends, therefore, the difference between physical and

psychological data is diminished. Is there ultimately no

difference, or do images remain as irreducibly and exclusively

psychological? In view of the causal definition of the difference

between images and sensations, this brings us to a new question,

namely: Are the causal laws of psychology different from those of

any other science, or are they really physiological?

 

Certain ambiguities must be removed before this question can be

adequately discussed.

 

First, there is the distinction between rough approximate laws

and such as appear to be precise and general. I shall return to

the former presently; it is the latter that I wish to discuss

now.

 

Matter, as defined at the end of Lecture V, is a logical fiction,

invented because it gives a convenient way of stating causal

laws. Except in cases of perfect regularity in appearances (of

which we can have no experience), the actual appearances of a

piece of matter are not members of that ideal system of regular

appearances which is defined as being the matter in question. But

the matter is. after all, inferred from its appearances, which

are used to VERIFY physical laws. Thus, in so far as physics is

an empirical and verifiable science, it must assume or prove that

the inference from appearances to matter is, in general,

legitimate, and it must be able to tell us, more or less, what

appearances to expect. It is through this question of

verifiability and empirical applicability to experience that we

are led to a theory of matter such as I advocate. From the

consideration of this question it results that physics, in so far

as it is an empirical science, not a logical phantasy, is

concerned with particulars of just the same sort as those which

psychology considers under the name of sensations. The causal

laws of physics, so interpreted, differ from those of psychology

only by the fact that they connect a particular with other

appearances in the same piece of matter, rather than with other

appearances in the same perspective. That is to say, they group

together particulars having the same “active” place, while

psychology groups together those having the same “passive” place.

Some particulars, such as images, have no “active” place, and

therefore belong exclusively to psychology.

 

We can now understand the distinction between physics and

psychology. The nerves and brain are matter: our visual

sensations when we look at them may be, and I think are, members

of the system constituting irregular appearances of this matter,

but are not the whole of the system. Psychology is concerned,

inter alia, with our sensations when we see a piece of matter, as

opposed to the matter which we see. Assuming, as we must, that

our sensations have physical causes, their