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

causal laws are

nevertheless radically different from the laws of physics, since

the consideration of a single sensation requires the breaking up

of the group of which it is a member. When a sensation is used to

verify physics, it is used merely as a sign of a certain material

phenomenon, i.e. of a group of particulars of which it is a

member. But when it is studied by psychology, it is taken away

from that group and put into quite a different context, where it

causes images or voluntary movements. It is primarily this

different grouping that is characteristic of psychology as

opposed to all the physical sciences, including physiology; a

secondary difference is that images, which belong to psychology,

are not easily to be included among the aspects which constitute

a physical thing or piece of matter.

 

There remains, however, an important question, namely: Are mental

events causally dependent upon physical events in a sense in

which the converse dependence does not hold? Before we can

discuss the answer to this question, we must first be clear as to

what our question means.

 

When, given A, it is possible to infer B, but given B, it is not

possible to infer A, we say that B is dependent upon A in a sense

in which A is not dependent upon B. Stated in logical terms, this

amounts to saying that, when we know a many-one relation of A to

B, B is dependent upon A in respect of this relation. If the

relation is a causal law, we say that B is causally dependent

upon A. The illustration that chiefly concerns us is the system

of appearances of a physical object. We can, broadly speaking,

infer distant appearances from near ones, but not vice versa. All

men look alike when they are a mile away, hence when we see a man

a mile off we cannot tell what he will look like when he is only

a yard away. But when we see him a yard away, we can tell what he

will look like a mile away. Thus the nearer view gives us more

valuable information, and the distant view is causally dependent

upon it in a sense in which it is not causally dependent upon the

distant view.

 

It is this greater causal potency of the near appearance that

leads physics to state its causal laws in terms of that system of

regular appearances to which the nearest appearances increasingly

approximate, and that makes it value information derived from the

microscope or telescope. It is clear that our sensations,

considered as irregular appearances of physical objects, share

the causal dependence belonging to comparatively distant

appearances; therefore in our sensational life we are in causal

dependence upon physical laws.

 

This, however, is not the most important or interesting part of

our question. It is the causation of images that is the vital

problem. We have seen that they are subject to mnenic causation,

and that mnenic causation may be reducible to ordinary physical

causation in nervous tissue. This is the question upon which our

attitude must turn towards what may be called materialism. One

sense of materialism is the view that all mental phenomena are

causally dependent upon physical phenomena in the above-defined

sense of causal dependence. Whether this is the case or not, I do

not profess to know. The question seems to me the same as the

question whether mnemic causation is ultimate, which we

considered without deciding in Lecture IV. But I think the bulk

of the evidence points to the materialistic answer as the more

probable.

 

In considering the causal laws of psychology, the distinction

between rough generalizations and exact laws is important. There

are many rough generalizations in psychology, not only of the

sort by which we govern our ordinary behaviour to each other, but

also of a more nearly scientific kind. Habit and association

belong among such laws. I will give an illustration of the kind

of law that can be obtained. Suppose a person has frequently

experienced A and B in close temporal contiguity, an association

will be established, so that A, or an image of A, tends to cause

an image of B. The question arises: will the association work in

either direction, or only from the one which has occurred earlier

to the one which has occurred later? In an article by Mr.

Wohlgemuth, called “The Direction of Associations” (“British

Journal of Psychology,” vol. v, part iv, March, 1913), it is

claimed to be proved by experiment that, in so far as motor

memory (i.e. memory of movements) is concerned, association works

only from earlier to later, while in visual and auditory memory

this is not the case, but the later of two neighbouring

experiences may recall the earlier as well as the earlier the

later. It is suggested that motor memory is physiological, while

visual and auditory memory are more truly psychological. But that

is not the point which concerns us in the illustration. The point

which concerns us is that a law of association, established by

purely psychological observation, is a purely psychological law,

and may serve as a sample of what is possible in the way of

discovering such laws. It is, however, still no more than a rough

generalization, a statistical average. It cannot tell us what

will result from a given cause on a given occasion. It is a law

of tendency, not a precise and invariable law such as those of

physics aim at being.

 

If we wish to pass from the law of habit, stated as a tendency or

average, to something more precise and invariable, we seem driven

to the nervous system. We can more or less guess how an

occurrence produces a change in the brain, and how its repetition

gradually produces something analogous to the channel of a river,

along which currents flow more easily than in neighbouring paths.

We can perceive that in this way, if we had more knowledge, the

tendency to habit through repetition might be replaced by a

precise account of the effect of each occurrence in bringing

about a modification of the sort from which habit would

ultimately result. It is such considerations that make students

of psychophysiology materialistic in their methods, whatever they

may be in their metaphysics. There are, of course, exceptions,

such as Professor J. S. Haldane,* who maintains that it is

theoretically impossible to obtain physiological explanations of

psychical phenomena, or physical explanations of physiological

phenomena. But I think the bulk of expert opinion, in practice,

is on the other side.

 

*See his book, “The New Physiology and Other Addresses” (Charles

Griffin & Co., 1919).

 

The question whether it is possible to obtain precise causal laws

in which the causes are psychological, not material, is one of

detailed investigation. I have done what I could to make clear

the nature of the question, but I do not believe that it is

possible as yet to answer it with any confidence. It seems to be

by no means an insoluble question, and we may hope that science

will be able to produce sufficient grounds for regarding one

answer as much more probable than the other. But for the moment I

do not see how we can come to a decision.

 

I think, however, on grounds of the theory of matter explained in

Lectures V and VII, that an ultimate scientific account of what

goes on in the world, if it were ascertainable, would resemble

psychology rather than physics in what we found to be the

decisive difference between them. I think, that is to say, that

such an account would not be content to speak, even formally, as

though matter, which is a logical fiction, were the ultimate

reality. I think that, if our scientific knowledge were adequate

to the task, which it neither is nor is likely to become, it

would exhibit the laws of correlation of the particulars

constituting a momentary condition of a material unit, and would

state the causal laws* of the world in terms of these

particulars, not in terms of matter. Causal laws so stated would,

I believe, be applicable to psychology and physics equally; the

science in which they were stated would succeed in achieving what

metaphysics has vainly attempted, namely a unified account of

what really happens, wholly true even if not the whole of truth,

and free from all convenient fictions or unwarrantable

assumptions of metaphysical entities. A causal law applicable to

particulars would count as a law of physics if it could be stated

in terms of those fictitious systems of regular appearances which

are matter; if this were not the case, it would count as a law of

psychology if one of the particulars were a sensation or an

image, i.e. were subject to mnemic causation. I believe that the

realization of the complexity of a material unit, and its

analysis into constituents analogous to sensations, is of the

utmost importance to philosophy, and vital for any understanding

of the relations between mind and matter, between our perceptions

and the world which they perceive. It is in this direction, I am

convinced, that we must look for the solution of many ancient

perplexities.

 

* In a perfected science, causal laws will take the form of

differential equations—or of finite-difference equations, if the

theory of quanta should prove correct.

 

It is probable that the whole science of mental occurrences,

especially where its initial definitions are concerned, could be

simplified by the development of the fundamental unifying science

in which the causal laws of particulars are sought, rather than

the causal laws of those systems of particulars that constitute

the material units of physics. This fundamental science would

cause physics to become derivative, in the sort of way in which

theories of the constitution of the atom make chemistry

derivative from physics; it would also cause psychology to appear

less singular and isolated among sciences. If we are right in

this, it is a wrong philosophy of matter which has caused many of

the difficulties in the philosophy of mind—difficulties which a

right philosophy of matter would cause to disappear.

 

The conclusions at which we have arrived may be summed up as

follows:

 

I. Physics and psychology are not distinguished by their

material. Mind and matter alike are logical constructions; the

particulars out of which they are constructed, or from which they

are inferred, have various relations, some of which are studied

by physics, others by psychology. Broadly speaking, physics group

particulars by their active places, psychology by their passive

places.

 

II. The two most essential characteristics of the causal laws

which would naturally be called psychological are SUBJECTIVITY

and MNEMIC CAUSATION; these are not unconnected, since the causal

unit in mnemic causation is the group of particulars having a

given passive place at a given time, and it is by this manner of

grouping that subjectivity is defined.

 

III. Habit, memory and thought are all developments of mnemic

causation. It is probable, though not certain, that mnemic

causation is derivative from ordinary physical causation in

nervous (and other) tissue.

 

IV. Consciousness is a complex and far from universal

characteristic of mental phenomena.

 

V. Mind is a matter of degree, chiefly exemplified in number and

complexity of habits.

 

VI. All our data, both in physics and psychology, are subject to

psychological causal laws; but physical causal laws, at least in

traditional physics, can only be stated in terms of matter, which

is both inferred and constructed, never a datum. In this respect

psychology is nearer to what actually exists.

 

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