What results for the problem of voluntary action if we apply to it the outcome
of the line of thinking followed so far? What happens if, e.g.. a person lifts his
hand and puts it on the table again? In order to avoid misunderstandings, we must
keep in mind that the fact of "two worlds" applies to every single trait
or content of experience and therefore is also valid for my own hand that I feel,
see, and in-fluence by my will, whose behavior we are now going to analyse. In this
case, too, it is indispensable to discriminate strictly between the "objective''
arm as a member of my organism, and the conscious image of it, which is a part of
my bodily ego that I can feel and see. As was said already, only this image can
be influenced immediately by our voluntary intentions. This discrimination follows
conclusively from the fact that, on the one hand, by anesthesizing the afferent
nerve tracks originating in a subject's arm and by simultaneously letting him shut
his eyes the arm disappears for the subject while for another observer it is just
as perceivable as before; and on the other hand, if a subject loses his objective
arm by an accident, his limb may persist being a more or less clearly perceptible
part of the bodily ego in the so-called phantom limb experiences. In the first case
the phenomenal, in the second the anatomical member of the two normally associated
counterparts is lacking. Furthermore, the decisive fact of two-ness is necessarily
also valid for the relations between the acting subject and the actions following
from his intentions as compared with the processes going on at the same time within
his organism as a result of efferent processes between his brain and its anatomical
extremities. My intention to lift up my right handy, e.g., can only be directed
to the phenomenal hand as a part of my phenomenal bodily ego but never directly
to the anatomical part of my organism that is related to the former and bears the
same name. Only by assuming this can the totality of phenomena involved in voluntary
action be accounted for without contradiction. To these belongs, among others, the
discrepancy between the region of the bodily ego on which our will immediately acts,
and the region of the organism that, at the same time, is subject to innervation.
As Julius PIKLER has shown long ago, the former region lies unmistakeably within
the hand itself as a part of the bodily ego, whereas the latter just as unmistakeably
lies within the muscular system of the upper arm and the shoulder of the anatomical
organism. In general, from the control of movement of the phenomenal arm there follows
a secondary control of the arm as a part of the organism which corresponds to the
former with admirable accuracy. But this precise reduplication of the phenomenal
motion by the objective motion is in no way a matter of course; on the contrary,
it borders on the miraculous. Nor does it work in every case. Under certain conditions
it fails. This is the case, among others, when a person acts in a dream, in the
hallucinations of motion due to affections of the brain by psychoses, lesions, or
poisoning, as well as in the illursory movement of phantom-limbs after amputation.
In this connection an observation I made sometime ago while awaking from a very
lively dream may be of interest. I had been rather active in that dream and when
I began to wake up my right arm was above my head. My theoretic interest awoke more
quickly than my body, so I could observe what now happened. The arm above my head
dissolved without moving, while another arm came into existence resting on my stomach,
an arm which obviously had objectively been there all the time.
This duplication of the environment as both a physical world of stimuli, distal
and proximal, and a phenomenal world of percepts - and also of one's own person
as both a physiological organism and a bodily ego - as has been said above already,
also refers to the mutual interaction between a person and his environment. But
as can be recognized from the prevailing use of the terms 'stimulus' and 'response'
in experimental psychology as well as in physiology and ethology, this reduplication
has not been taken into amount in most cases. In practice we are compelled by the
facts to differentiate the concept of stimulus into two clearly distinguishable
sub-concepts. The first sub-concept of stimulus means the physico-chemical processes
that act on the receptor-cells of the organism; the second is a little mo-re intricate,
as we shall see immediately.
The response of the organism to a stimulus in the first sense may be of two different
types. The first type consists in an organic change or process (such as the production
of saliva or the contraction of the pupil), frequently without any concomitant conscious
phenomena. In the second type of response two phases must be distinguished. In the
first phase, something happens in the phenomenal world (a new percept appears, an
existing one changes or moves or disappears etc.). In the second phase this new
phenomenon acts upon the ego or subject, e.g. attracts his attention or scares him
away. It may also invite him to handle it in a certain manner. For these characteristics
of percepts (not of stimuli in the first sense!) Kurt LEWIN introduced the German
term "Aufforderungscharakter'', which was transla-ted into English by "valence".
This action of a percept on the ego may also be cal-led stimulation, though not
in a physiological but only in a psychological sense. In everyday German, we also
use for this the term "Reiz'', the literal translation of stimulus (as in "ein
reizendes Mädchen'') while in English, expressions such as 'attractiveness',
'appeal', are preferred. One thing must be kept in mind: the events I have just
been dealing with occur between the percept and the ego within the phenomenal world
and not between the physical surroundings and the organism; in other words, not
between stimuli in the first sense and perceptors. If, notwithstanding, it is customary
in behaviorist psychology to call "stimulus'' a female, or an enemy, or a mate,
or an offspring, or some prey animal, it must be clear that in doing so the objective
level of physico-chemical and physiological processes, with which it was supposed
to deal exclusively, has been left behind.
We must treat the concept of response in exact analogy with what has been said
above. This term also has two meanings. In the first sense, it refers to the changes
in positions of various parts of the phenomenal bodily ego, including any preceding
changes of attitudes, emotions, and intentions; in the second sense, to the execution
by the extremities of the organism of the intended movement which, as we have already
mentioned, does not occur when a person dreams and therefore must logically be distinguished
from the response in the first sense.
I come now to my crucial point, namely to the question: what is the use of this
duplication of the world into a physical and a perceptive one, of the person into
an organism and a bodily ego, of stimulation into configurations of physico-chemical
impacts upon receptors and valences affecting the ego, and of reaction into intended
changes of the bodily ego and motions executed by parts of the organism? What relevance
can all this have? It is extremely improbable that so highly complicated an organization
could have developed during evolution and preserved without a considerable survival
value. And it seems to me that this value can clearly be de-monstrated.
We begin with the action side of the picture. Here we find a striking similarity
to the well-known technical servo-mechanisms, e.g., the mechanical steering of a
large vessel. To illustrate this by the simplest parallel: Instead of a direct connection
between the steering-wheel and the rudder there is a two-step connection. The first
step connects the bridge with the steering machine, the second the machine with
the rudder. Instead of the wheel it suffices to have a small lever that can be turned
easily, while the hard work of turning the heavy rudder through highly resistant
water is done by the machine according to the information given it by the lever.
The phenomenal arm as perceived by the subject which is dependent on his will
corresponds to the lever as handled by the helmsman. The arm as part of the organism
corresponds to the rudder, and the musculature bringing the organismic arm into
the position prescribed by the motion intended for the phenomenal arm corresponds
to the steering-machine that moves the rudder according to the position of the lever.
It is true there is a difference between the nervous and the technicaI servome-chanisms,
which I will try to point out now. Mechanically it is possible to fix on the shaft
of the first lever a second one that indicates the actual position of the rudder
and its deviation from the intended position, coinciding with the first lever when
the intended position is reached by the rudder.
In the neural mechanism there is no second lever. The lever is constructed in
such a way that it indicates the true effect of the intention to move at the same
time. This comes about by the following trick. This lever - we mean always the arm
as part of the bodily ego - cannot move independently from the "rudder"
viz. the arm as part of the organism and therefore cannot run ahead of it. That
means that even the least "pressure'' acting upon the "lever'' puts the
organismic arm in motion, and the lever is brought into its intended position by
the activity of the organismic arm in moving to the intended position. This, of
course, presupposes that the reactions of the "steering machine'' are extraordinarily
quick, in other words, that it reacts to minimal dislocations of the lever, and
practically without delay. Some years ago I discussed this principle of construction
with a group of specialists in cybernetics and, according to their judgments such
a construction is theoretically possible. Considering the variety and variability
of active human (and vertebrate) motion, its advantages are obvious. Perhaps under
the conditions of human action it is the only one that works.
So far I have discussed a rather simple but relatively unnatural case, a case
in which the subject is alone with one of his limbs and the intended position of
this limb is fixed arbitrarily by the subject. In order to transfer the idea to
a more important situation, viz. the subject's interaction with other things or
beings, above all with those objects which serve to gratify his needs or to carry
out his intentions, we have to take a glance at the other side of the matter, at
the side of the object. Here, too, the analogy of orienting oneself in his surroundings
by using a periscope is obvious to the engineer. This periscope differs from the
normal type by the fact that the observer does not look outward through a set of
lenses and prisms but observes an image that is projected on a plane inside the
whole system just as is the image of the sun in the well known Einstein-tower at
Potsdam. But this image differs from the image of the sun in the astronomical device
in that its parts are more than a mosaic whose elements reject light more or less
apart from any dynamic interaction. In consciousness these parts are units dynamically
segregated from each other and coherent in themselves, tightly packed within a narrow
cerebral field, one of them being the unit representing one's own ego. Hereby, dynamic
interaction of a nature not yet sufficiently known becomes possible between these
units corresponding to the organism and the objects of its environment, interaction
that is unmistakeably lacking in the space between the physiological organism and
its physical objects but is necessary for a meaningful and biologically beneficial
interaction between the person and his environment.
The function of the phenomenal world, then, would be to make possible just those
dynamic interactions and to transfer them to the organism through an intricate system
of circular conductors that allow for the necessary feedback in such a way that
the organism itself is made to behave "with regard to" the objects encountered
in its environment and relevant for its survival.
The following considerations aim at developing some of the fundamental features
of this idea. They start from three facts that are characteristic both for the satisfaction
of needs and for the execution of intentions. I shall try to make these clear by
a second diagram (Figure 2) in which you see various symbols for phenomenal objects
related to different needs at the upper left, the phenomenal ego with some patterns
of action correlated to these needs at the lower left, and on the right the subcortical
centers of needs.

Now, when the tension of a need (n1) increases above its
threshold, or when the time of execution of an intention approaches, several things
happen.
1) Given certain circumstances, a pattern of action (m1)
is activated and put into readiness within the phenomenal ego. Therefore, the system
of needs exerts an influence on the motor or executive system - which is quite plausible.
2) In the phenomenal environment the objects (D1) that
correspond to (or, more exactly, the IRMs by which they are characterized as such)
- or the objects to which a given intention refers - are accentuated. They begin
to attract attention. That means that there is also an influence from the centers
of need on the system of perception. The objects to which a need refers seem to
be activated by something like resonance. Whether these objects are determined by
heredity, or by imprinting, or by conditioning - or are established deliberately
by an intention - does not make a difference.
The two effects just described do not exist independently from one another. Rather
3) the field between the phenomenal ego and the phenomenal object of the need
or intention is being polarized, so that attracting or repelling forces come into
existence between them. These are experienced more or less strongly as appeal or
threat, and are often irresistible. This polarization of the field between the phenomenal
object and the subject underlies the directed component of all instinctive or intentional
behavior, without which no activity can ever reach its aim. The interrelations between
the subject and the object, as described above, become themselves a steering mechanism,
in which - in the case of attraction - the place of the phenomenal object represents
the value aimed at, the position of the subject the actual value, and consequently
the distance between them represents the difference between these two values by
which the human steering machine viz. the muscular system is set in motion so that
in the physical world the distance between the organism and the object diminishes
and finally disappears.
In the case of negative polarization or repulsion, the situation is somewhat
different. Repulsion merely causes flight or retreat of the subject, that is, an
increase in the distance between the subject and the object, until the threat becomes
subliminal. In this moment the whole affair is settled and nothing more happens.
(It seems to me to be significant that - as has been observed repeatedly - repulsion
goes on along the force lines originating in the threatening objects even if another
direction of movement would be more suitable.)
But let us return to the case of attraction. Here the approach toward the object
is but the first phase of the whole process. At its completion, in the moment when
the distance disappears, a second phase is immediately initiated viz. the execution
of the innate or learned pattern of performance - or the intended activity - which
up to this moment was ready for action but had been blocked, is now set free. Not
until then could the tension caused by the need or intention be definitely released
- provided that the object is appropriate. If this is the case, the much discussed
reinforcement takes place, that is to say the connection between the pattern of
the object and the pattern of action by which the accentuation of the object in
the field of perception and the subsequent polarization will be intensified later
on while at the same time it will be restricted to a class of objects that will
become more and more sharply defined. This coupling and its storage I have localized
hypothetically in the region of the center of need. But possibly this hypothesis
will have to be revised some day.