Mach and Ehrenfels: Foundations of Gestalt Theory
Mach and Ehrenfels:
The Foundations of Gestalt Theory(1)
Kevin Mulligan and Barry Smith
From Barry Smith (ed.), Foundations of Gestalt Theory,
Munich and Vienna: Philosophia, 1988, 124-57.
§ 1. Preamble
One important measure of the success of
a philosophy of science is the extent to which the clarifications which
it yields have positive and fruitful consequences within the sciences themselves.
Such success is at least in part a function of the extent to which its
examples and problems are taken over from genuine science and are not merely
trivial or over-simplified illustrations. The thought of Mach in particular,
and of Austrian philosophers of science in general, provides us with striking
examples of such interaction. Mach's epistemology and ontology grew out
of his investigations, both systematic and historical, in physics and psychology,
and they contributed in turn to the further development of his own thinking
in these areas and to the work of those, such as Einstein and Ehrenfels,
whom he influenced. Similarly, it was the interaction between philosophy
and psychology which made possible the seminal work on the notion of Gestalt
quality by Ehrenfels, and this work, together with the writings on the
logic and ontology of parts, wholes and structures by other members of
the Brentano school, led in turn to significant further developments, not
only in psychology itself, but also in neighbouring disciplines such as
linguistics.(2)
We shall find in what follows that we can
come to terms with the implications of the ideas of Mach and Ehrenfels
on the perception of what is complex and on the complexity of perception
only by paying especially detailed attention to their respective understandings
of the notion of non-causal dependence. The clarification of this
notion - first effected in a truly systematic way in the writings of these
two authors and in those of their contemporaries Brentano and Stumpf -
is, we shall argue, one of the great achievements of Austrian philosophy
of science. Mach, it will turn out, was unable successfully to incorporate
his descriptions of complex perception within his general atomistic framework
in no small part because his understanding of dependence was in a quite
specific sense too narrow. The great significance of the work of Ehrenfels
and of other members of the Brentano tradition from our point of view is
that, because they were more faithful to the structures of what is given
in perception, they were able to develop a richer theory of dependence,
the implications of which were to extend far beyond the narrow sphere of
perceptual psychology.
§ 2. The Problem of the Perception
of Complexes
To talk of a 'perception of what is complex'
is, from the atomistic perspective which held sway amongst the majority
of nineteenth century psychologists, already to employ a form of speech
that is illegitimate in the sense that it is not grounded in any underlying
reality. There is at most, according to the atomistic psychologist, the
possibility of a summation of simple perceivings, each one of which
would have something unitary or non-complex as its object or content.(3)
Mach, too, embraced an atomism of this
kind. For him all complexes, including the ego itself, are mere ideal,
practical or provisional 'mental-economic unities'. As he puts it in the
Analyse
der Empfindungen, only the 'elements' (sensations, Empfindungen)
are real.(4) But he clearly saw that there
is a problem of complex perception,(5)
and Ehrenfels, as is well known, was able to take certain passages from
this work as the starting- point of his investigation of complex-perception
in his classic essay of 1890, "Über 'Gestaltqualitäten'". These
passages are not isolated instances of what might be taken to be less than
careful thinking on Mach's part. Indeed the examination of Mach's writings
reveals that his anticipation of Ehrenfels goes back at least 20 years
earlier. On receipt of Ehrenfels' paper, Mach replied in a letter that
he had already put forward the main ideas - albeit in a more psychological
way, in terms of a theory of 'muscular sensations' - in an earlier paper.
The paper in question is almost certainly
his "Bemerkungen zur Lehre vom räumlichen Sehen" of 1865,(6)
a critical discussion of the psychology of Herbart dealing specifically
with the problem of our recognition of perceptual complexes. How, Mach
asks, do we recognise different spatial figures ('Gestalten') as
the same? How does it come about that we apparently recognise melodies
as being alike? How is it that we recognise the form of a melody more easily
than the key in which it is played? Why is it that we recognise a rhythm
more easily than an absolute duration? Where is the similarity between
the individual, unitary qualities presented in the hearing of a melody
played on a trumpet in the key of C, and those presented in the hearing
of 'the same' melody played on a violin in G? Recognition and likeness
here, as Mach points out,
cannot depend on the qualities
of the perceptual presentations [Vorstellungen], for these are different.
On the other hand recognition, according to the principles of psychology,
is possible only on the basis of presentations which are the same in quality
(Mach 1865, p. 122 of repr., Eng. p. 391, quoted in Schulzki, p. 42).
There is, Mach concludes,
no other alternative but for us
to consider the qualitatively dissimilar presentations in the two series
as being necessarily connected with some sort of qualitatively
similar presentations. (loc. cit., our emphasis)
Mach, that is to say, claims that there
is a means of solving the problem of complex perception within the atomistic
framework by means of an appeal to additional elementary sensations outside
the sphere of perception, sensations he calls Muskelempfindungen.
When we hear the same melody in two different keys, our apprehension of
this 'sameness' rests on the fact that, for all the differences in tone-sensations,
the same feeling-sensations are involved in both cases. On a trivial interpretation,
Mach here is presenting a view according to which our experience enjoys
a certain sort of double structure, each separate experience of the individual
tones in a melody or of the points in a spatial figure is coloured by a
certain element of feeling. It remains the case that, on this modified
view of 'element', experience is just one damned element after another.
Such a view is indeed able to solve the
problem of identity of complex objects of experience, at least for simple
cases, but it is not only this problem which an account of our perception
of what is complex is called upon to resolve. Such an account must explain
also the unity of complexes that is given in experience, and it
must do justice to the fact that complexes are given in such a way as to
be demarcated from other, neighbouring complexes in such a way as to form
unified and integral wholes. And Mach's account, on this interpretation,
is inadequate to features such as this.
There is, however, another, more subtle
interpretation of Mach's position, the possibility of which we almost certainly
owe to Ehrenfels, since it consists in a certain sense in reading back
Ehrenfels' ideas on Gestalt qualities into the relevant Machian texts.
According to this interpretation, it is not the successive elementary successions,
but rather each apparent complex perception that comes to be associated
with its own characteristic feeling-sensation or nervous quale.
The existence of similarities between such quale can then explain
both how it is that we can enjoy the appearance of what is putatively the
same
complex even where the associated elementary data of perception are in
fact distinct, and also how it is that the apparent complex in question
is given as something unitary and as something set apart from its environment.
Thus when I see a square, for example,
then in addition to the perceived elements (whether these be conceived
as points, lines or segments) there is also a peculiar nervous sensation
which I have as a result of the innervations of the muscles of my eyes,
a sensation that is repeated, spontaneously and without any effort on my
part, whenever I see a similar figure. The body as a whole we might
say, in consort with specific sensory presentations of what is simple,
is to do the job of accounting for our apparent presentation of what is
complex. And we should, as Mach himself argues, look to the variety of
the human organism,
which is provisionally rich enough
to cover the outlays of psychology in this regard - and it is high time
that we took seriously the talk of 'bodily resonance' in which psychology
has so readily engaged. (1865, loc. cit., Eng. p. 392)(7)
Now an account of this kind works well
enough, on its own terms, in relation to our (apparent) perceptions of
congruent but differently coloured spatial shapes (space and shape, we
note, are the subject-matter of Mach's 1865 paper). Each such shape can
indeed be seen as being associated - 'necessarily connected', as Mach puts
it - with its own characteristic muscular innervation, itself derived from
corresponding motor processes of the eye and head. (Modern-day psychologists,
with their investigation of the role of the kinaesthetic dimension in experience,
have at least to some extent vindicated Mach in this regard.) We are interested,
however, in a general theory of complex perception. Indeed Mach himself
writes:
Just as the same, differently
coloured forms, the same muscular sensations, must occur if the forms are
to be recognised as the same, so too each and every form, each and every
abstraction, as one might say, must in just the same way be based upon
presentations of a quite particular quality. This holds true for space
and shape, as well as for time, rhythm, pitch, the form of melodies, intensity,
and so on. (loc. cit., Eng. p. 391f.)
Mach assumes, that is to say, that it is
possible to generalise the theory of muscular sensations to encompass all
sensory dimensions. More, that it is in principle possible to extrapolate
from this theory in such a way as to encompass our apparent presentation
of all 'Abstraktionen' from what is given.(8)
Ehrenfels, too, recognised the necessity
of such a general theory of complex perception.(9)
But he saw also - and this was a significant achievement of "Über
'Gestaltqualitäten'" - that a completely general theory could not
be obtained on the basis of an appeal to additional elementary phenomena
along the lines of Mach's muscular sensations. For such sensations can
at best explain our apparent perception of what is complex only in relation
to what is non-temporal, of what is capable of being presented instantaneously,
i.e. simple spatial figures, simple smells, simple musical chords. There
is no way in which an appeal to extra elementary (and thus instantaneous)
sensations alone can solve the ontological problem raised by our (apparent)
perception of temporally extended, unitary complexes such as melody and
rhythm, and in general of all Gestalten involving change and motion. For
there is clearly no answer to the question as to when a single elementary
feeling-sensation - putatively associated with a plurality of elementary
perceptions spread out in time - could become associated with this plurality
in the relevant way.(10)
The elementary innervation (or what have
you) can do service for the perception of what is complex only if it is
somehow associated with all relevant perceptions. This association
can come about, however, only if these perceptions are already collected
together,
e.g. through the operations of memory, to form a single and instantaneous
composite perception. But the appeal to such a composite perception clearly
signifies a departure from the atomistic perspective. Moreover, once such
composites have been accepted, it is difficult to see what explanatory
role could remain for any associated muscular innervations.
For reasons to be investigated only later,
Mach need not acknowledge that this argument has isolated any inadequacy
in his account, since he rejects the notion of time as traditionally conceived;
the very concepts of simultaneity and non-simultaneity are held by him
to correspond to no underlying reality.
It is not, however, this inadequacy of
Mach's account which will be of interest to us here. Our attention will
be directed, rather, toward the nature of the relation between muscular
and perceptual quale that is presupposed by his theory.
§ 3. The Analysis of Sensations
The theory of Muskelempfindungen
of 1865 is not simply abandoned by Mach in his later writings. Many of
the same ideas are at work also in the Analyse der Empfindungen,
though now the theory of muscular sensations has been extended - legitimately
or not - to embrace a taxonomy of different kinds of 'space-sensations',
'time-sensations' and in principle also muscular innervations of other
sorts - illustrating Mach's faith in the 'power and variety of the human
organism'.
Thus consider the following passage quoted
by Ehrenfels at the beginning of his paper:
In melodic as well as in harmonic
combinations, notes whose rates of vibration bear to one another some simple
ratio are distinguished (1) by their agreeableness, and (2) by a sensation
characteristic of this ratio. (1886, p. 130; Eng. p. 138)(11)
Such distinctiveness manifests itself also
in our forms of expression:
Colours, sounds, temperatures,
pressures, spaces, times and so forth are connected with one another in
manifold ways; and with them are associated moods of mind, feelings and
volitions. Out of this fabric, that which is relatively more fixed and
permanent stands prominently forth, engraves itself in the memory, and
expresses itself in language. (1886, p. 2, Eng. p. 2)
What is missing from the Analyse der
Empfindungen - and this is a crucial development - is any talk of a
'necessary connection' or 'intimate mutual relation' such as we find in
the 1865 account.(12) We now learn only
that the characteristic sensations are 'connected to' or 'dependent on'
the elements with which they are associated. Further, this dependence is
seen as being in every case relative to the perspective or point of view
adopted by the investigator:
A colour is a physical object
as long as we consider its dependence upon its luminous source (other colours,
heat, spaces, etc.). But if we consider its dependence upon the retina...then
it is a psychological object, a sensation. (1886, p. 13, Eng., p. 14f.)
We shall turn below to the task of examining
in detail just what Mach understood by 'dependence' here. For the moment
it is sufficient to note that it is not any sort of causal relation. Causality
is rejected by Mach as a metaphysical encumbrance, an anthropomorphic notion,
properly to be eliminated from any science that is worthy of the name.
§ 4. On Gestalt Qualities
Ehrenfels, too, employs a notion of non-causal
dependence in his theory. But for him it is the Gestalt qualities themselves,
certain sui generis objects of presentation, which are dependent
on the data of sensation which are their foundation.
Ehrenfels seeks to be faithful to the reality
(veridicality) of our perception of what is complex. There is something
there,
he insists, which we perceive through specific types of complex networks
of acts of presentation (perception, memory and imagination) of what is
simple, whenever we perceive a melody, a rhythm, or any other Gestalt quality.
And he claims further that, to produce a truly faithful account of our
perception of such formations we have to distinguish objects of perception
on two distinct levels.
Ehrenfels recognises not only complexes
of elementary perceptual data but also special qualities of such
complexes, and the formations we perceive are such as to involve both.
Just as for Mach, if two figures are similar, then this is because of an
identity in the appurtenant nerve-processes or feeling-sensations, so also
for Ehrenfels, if two figures are similar, then this is because of an identity
in their associated Gestalten.(13)
Ehrenfels is explicit that this identity
is to be explained by appeal to unitary presentational elements: when we
hear a melody consisting of 8 notes, then there are (at least) nine presentations
involved, 8 aural presentations of individual notes, and one unitary presentation
of the associated Gestalt quality.(14)
Ehrenfels acknowledges that the notes constitute in and of themselves a
certain complex whole, and that the Gestalt quality is founded upon (is,
precisely, a 'quality of') this complex whole. But the quality itself is
not a whole embracing the individual sensational elements as parts: a view
of this sort was developed only with the work of Wertheimer and the other
members of the Berlin School. In this respect Ehrenfels, like Mach, can
be said to have offered an elementarist solution to the problem of complex
perception.
For Ehrenfels, as for Mach, no special
intellectual effort, attention or attitude is needed to produce the awareness
of a Gestalt quality: this awareness occurs as it were automatically. The
problem of the 'universal givenness of Gestalt qualities with their foundations'
is however a complex one. Ehrenfels asserts that
wherever a complex which can serve
as the foundation for a Gestalt quality is present in consciousness, this
quality is itself eo ipso and without any contribution on our part
also given in consciousness (translation, p. 111).
This remark relates only to the issue of the
genesis
of Gestalt qualities, to the question whether, on the basis of a given
foundation, any activity or assistance is required on our part in order
to bring a Gestalt quality to consciousness. Thus Ehrenfels points out
that, at least in certain cases,
the exertion we seem to require
in order to grasp a shape or melody on the basis of a foundation already
presented is much rather applied to the filling out of that foundation
itself. (translation, p. 111)
He considers our perception of paintings,
where sensation yields merely a starting point for further imaginative
filling out:
A significant exercise of our
capacities is required in order to utilise in our presentation the slight
distinctions in light and colour and the foreshortenings in the perspective
plane as associative tokens for the realisation of the total luminosity
and three-dimensionality of the painting. (translation, pp. 111 f.)
But effort is needed, Ehrenfels argues, only
in order to fix the indirectly seen parts of the whole. Someone who has
developed in his consciousness the foundation for the Gestalt quality in
the appropriate way will not find it necessary to generate this quality
itself in a further act - and nor will he have any choice as to which
quality will be generated: the quality is, as it were, given of itself.
Ehrenfels' views on the genesis of Gestalt qualities are in this respect
identical to those of Mach on the genesis of muscular innervations.
There is, however, in addition to the question
of the genesis of Gestalt qualities also another question, that of the
ontological status of such qualities, and of their constitutive relations
to the sensory data with which they are associated.(15)
Ehrenfels was perhaps the first to consider this problem in a serious way.
He points out that if we assert a mutual dependence of Gestalt quality
and foundation not merely in the genetic but also in this ontological sense,
then this gives rise immediately to a problem of infinite multiplication.
Mutual ontological foundation would signify first of all, harmlessly enough,
that every Gestalt quality is necessarily such that it could not exist
unless there exists also a corresponding complex of fundamenta. But it
would signify also that every complex of fundamenta, too, is necessarily
such that it could not exist unless an associated Gestalt quality existed
also. Every arbitrary complex of given sensations, however delineated,
would give rise to a Gestalt quality of its own. This would imply, however,
that we would once more be in no position to explain that characteristic
unity and integrity of perceptual complexes which is in fact experienced.
Thus to hear a melody (e.g.) would be to hear also all constituent sub-melodies
(and indeed, unless constraints on temporal and spatial proximity are introduced,
all melodies built up on the basis of presently perceived tones together
with tones previously heard). But further, since Gestalt qualities are
themselves perfectly valid objects of presentation which may themselves
serve as fundaments of further Gestalt qualities, it would follow that,
on hearing a sequence (s1, s2,...,sn)
of tones, we have not only the Gestalt quality, say f1
which these immediately generate, but also the further Gestalt qualities
f2
- generated by the sequence - (s1,
s2,...,sn,
f1) - the quality f3 - generated by
the sequence (s1,
s2,...,sn,
f1, f2) - and so on. Now clearly, as
Ehrenfels would say, there is nothing of all of this given in inner perception.
And he concludes that, in the ontological sense, Gestalt qualities are
merely one-sidedly dependent on their fundamenta.(16)
Mach seems not to have faced this problem, even though it arises in the
self-same way within the framework of his own nervous quale theory.
He seems, rather, to have run together the genetic and the ontological
dimensions and thereby to have been constrained to accept mutual dependence
both in the genetic and in the ontological sense. As Smith points out in
his essay above, the Meinongians accepted it in neither sphere, insisting
on a one-sided dependence both genetically and ontologically. Thus they
held first of all that Gestalt qualities (now called 'founded contents'
and later 'higher order objects', or 'objects of presentations of extra-sensory
provenance') are one-sidedly ontologically dependent ('founded') on their
fundamenta or 'inferiora'. But they held also that such qualities are in
need of being produced for presentation by a special exertion of
consciousness, that the Gestalt quality must in a certain sense be teased
out of the perceptual environment.(17)
We might display the essentials of Ehrenfels'
account in the form of a diagram, somewhat as follows:
Diagram 1.
Here the arrows represent relations of
intentional directedness (between an act and its object), and the double
lines represent relations of mutual dependence.
Mach's theory, on the other hand, on the
interpretation here advanced, might look like this:
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