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

perform it more skilfully, or even to suppress it

altogether. Actions of this kind, with which instinct and

volition enter upon equal terms, have been called ‘semi-reflex.’

The act of running towards the train, on the other hand, has no

instinctive element about it. It is purely the result of

education, and is preceded by a consciousness of the purpose to

be attained and a distinct mandate of the will. It is a

‘voluntary act.’ Thus the animal’s reflex and voluntary

performances shade into each other gradually, being connected by

acts which may often occur automatically, but may also be

modified by conscious intelligence.

 

“An outside observer, unable to perceive the accompanying

consciousness, might be wholly at a loss to discriminate between

the automatic acts and those which volition escorted. But if the

criterion of mind’s existence be the choice of the proper means

for the attainment of a supposed end, all the acts alike seem to

be inspired by intelligence, for APPROPRIATENESS characterizes

them all alike. “

 

There is one movement, among those that James mentions at first,

which is not subsequently classified, namely, the stumbling. This

is the kind of movement which may be called “mechanical”; it is

evidently of a different kind from either reflex or voluntary

movements, and more akin to the movements of dead matter. We may

define a movement of an animal’s body as “mechanical” when it

proceeds as if only dead matter were involved. For example, if

you fall over a cliff, you move under the influence of

gravitation, and your centre of gravity describes just as correct

a parabola as if you were already dead. Mechanical movements have

not the characteristic of appropriateness, unless by accident, as

when a drunken man falls into a waterbutt and is sobered. But

reflex and voluntary movements are not ALWAYS appropriate, unless

in some very recondite sense. A moth flying into a lamp is not

acting sensibly; no more is a man who is in such a hurry to get

his ticket that he cannot remember the name of his destination.

Appropriateness is a complicated and merely approximate idea, and

for the present we shall do well to dismiss it from our thoughts.

 

As James states, there is no difference, from the point of view

of the outside observer, between voluntary and reflex movements.

The physiologist can discover that both depend upon the nervous

system, and he may find that the movements which we call

voluntary depend upon higher centres in the brain than those that

are reflex. But he cannot discover anything as to the presence or

absence of “will” or “consciousness,” for these things can only

be seen from within, if at all. For the present, we wish to place

ourselves resolutely in the position of outside observers; we

will therefore ignore the distinction between voluntary and

reflex movements. We will call the two together “vital”

movements. We may then distinguish “vital” from mechanical

movements by the fact that vital movements depend for their

causation upon the special properties of the nervous system,

while mechanical movements depend only upon the properties which

animal bodies share with matter in general.

 

There is need for some care if the distinction between mechanical

and vital movements is to be made precise. It is quite likely

that, if we knew more about animal bodies, we could deduce all

their movements from the laws of chemistry and physics. It is

already fairly easy to see how chemistry reduces to physics, i.e.

how the differences between different chemical elements can be

accounted for by differences of physical structure, the

constituents of the structure being electrons which are exactly

alike in all kinds of matter. We only know in part how to reduce

physiology to chemistry, but we know enough to make it likely

that the reduction is possible. If we suppose it effected, what

would become of the difference between vital and mechanical

movements?

 

Some analogies will make the difference clear. A shock to a mass

of dynamite produces quite different effects from an equal shock

to a mass of steel: in the one case there is a vast explosion,

while in the other case there is hardly any noticeable

disturbance. Similarly, you may sometimes find on a mountain-side

a large rock poised so delicately that a touch will set it

crashing down into the valley, while the rocks all round are so

firm that only a considerable force can dislodge them What is

analogous in these two cases is the existence of a great store of

energy in unstable equilibrium ready to burst into violent motion

by the addition of a very slight disturbance. Similarly, it

requires only a very slight expenditure of energy to send a

post-card with the words “All is discovered; fly!” but the effect

in generating kinetic energy is said to be amazing. A human body,

like a mass of dynamite, contains a store of energy in unstable

equilibrium, ready to be directed in this direction or that by a

disturbance which is physically very small, such as a spoken

word. In all such cases the reduction of behaviour to physical

laws can only be effected by entering into great minuteness; so

long as we confine ourselves to the observation of comparatively

large masses, the way in which the equilibrium will be upset

cannot be determined. Physicists distinguish between macroscopic

and microscopic equations: the former determine the visible

movements of bodies of ordinary size, the latter the minute

occurrences in the smallest parts. It is only the microscopic

equations that are supposed to be the same for all sorts of

matter. The macroscopic equations result from a process of

averaging out, and may be different in different cases. So, in

our instance, the laws of macroscopic phenomena are different for

mechanical and vital movements, though the laws of microscopic

phenomena may be the same.

 

We may say, speaking somewhat roughly, that a stimulus applied to

the nervous system, like a spark to dynamite, is able to take

advantage of the stored energy in unstable equilibrium, and thus

to produce movements out of proportion to the proximate cause.

Movements produced in this way are vital movements, while

mechanical movements are those in which the stored energy of a

living body is not involved. Similarly dynamite may be exploded,

thereby displaying its characteristic properties, or may (with

due precautions) be carted about like any other mineral. The

explosion is analogous to vital movements, the carting about to

mechanical movements.

 

Mechanical movements are of no interest to the psychologist, and

it has only been necessary to define them in order to be able to

exclude them. When a psychologist studies behaviour, it is only

vital movements that concern him. We shall, therefore, proceed to

ignore mechanical movements, and study only the properties of the

remainder.

 

The next point is to distinguish between movements that are

instinctive and movements that are acquired by experience. This

distinction also is to some extent one of degree. Professor Lloyd

Morgan gives the following definition of “instinctive behaviour”:

 

“That which is, on its first occurrence, independent of prior

experience; which tends to the well-being of the individual and

the preservation of the race; which is similarly performed by all

members of the same more or less restricted group of animals; and

which may be subject to subsequent modification under the

guidance of experience.” *

 

* “Instinct and Experience” (Methuen, 1912) p. 5.

 

This definition is framed for the purposes of biology, and is in

some respects unsuited to the needs of psychology. Though perhaps

unavoidable, allusion to “the same more or less restricted group

of animals” makes it impossible to judge what is instinctive in

the behaviour of an isolated individual. Moreover, “the

well-being of the individual and the preservation of the race” is

only a usual characteristic, not a universal one, of the sort of

movements that, from our point of view, are to be called

instinctive; instances of harmful instincts will be given

shortly. The essential point of the definition, from our point of

view, is that an instinctive movement is in dependent of prior

experience.

 

We may say that an “instinctive” movement is a vital movement

performed by an animal the first time that it finds itself in a

novel situation; or, more correctly, one which it would perform

if the situation were novel.* The instincts of an animal are

different at different periods of its growth, and this fact may

cause changes of behaviour which are not due to learning. The

maturing and seasonal fluctuation of the sex-instinct affords a

good illustration. When the sex-instinct first matures, the

behaviour of an animal in the presence of a mate is different

from its previous behaviour in similar circumstances, but is not

learnt, since it is just the same if the animal has never

previously been in the presence of a mate.

 

* Though this can only be decided by comparison with other

members of the species, and thus exposes us to the need of

comparison which we thought an objection to Professor Lloyd

Morgan’s definition.

 

On the other hand, a movement is “learnt,” or embodies a “habit,”

if it is due to previous experience of similar situations, and is

not what it would be if the animal had had no such experience.

 

There are various complications which blur the sharpness of this

distinction in practice. To begin with, many instincts mature

gradually, and while they are immature an animal may act in a

fumbling manner which is very difficult to distinguish from

learning. James (“Psychology,” ii, 407) maintains that children

walk by instinct, and that the awkwardness of their first

attempts is only due to the fact that the instinct has not yet

ripened. He hopes that “some scientific widower, left alone with

his offspring at the critical moment, may ere long test this

suggestion on the living subject.” However this may be, he quotes

evidence to show that “birds do not LEARN to fly,” but fly by

instinct when they reach the appropriate age (ib., p. 406). In

the second place, instinct often gives only a rough outline of

the sort of thing to do, in which case learning is necessary in

order to acquire certainty and precision in action. In the third

place, even in the clearest cases of acquired habit, such as

speaking, some instinct is required to set in motion the process

of learning. In the case of speaking, the chief instinct involved

is commonly supposed to be that of imitation, but this may be

questioned. (See Thorndike’s “Animal Intelligence,” p. 253 ff.)

 

In spite of these qualifications, the broad distinction between

instinct and habit is undeniable. To take extreme cases, every

animal at birth can take food by instinct, before it has had

opportunity to learn; on the other hand, no one can ride a

bicycle by instinct, though, after learning, the necessary

movements become just as automatic as if they were instinctive.

 

The process of learning, which consists in the acquisition of

habits, has been much studied in various animals.* For example:

you put a hungry animal, say a cat, in a cage which has a door

that can be opened by lifting a latch; outside the cage you put

food. The cat at first dashes all round the cage, making frantic

efforts to force a way out. At last, by accident, the latch is

lifted. and the cat pounces on the food. Next day you repeat the

experiment, and you find that the cat gets out much more quickly

than the first time, although it still makes some random

movements. The third day it gets out still more quickly, and

before long it goes straight to the latch and lifts it at once.

Or you make a model of the Hampton Court maze, and put a rat in

the middle, assaulted by the smell of