Three modes of knowledge as basis for intercultural cognition and communication – A theoretical perspective

Ernst Pöppel, Yan Bao

Human Science Center, Ludwig Maximilian University, Munich, Germany
Parmenides Centers for the Study of Thinking, Pullach im Isartal, Germany

Department of Psychology, Peking University, Beijing, China

Running head:  Three modes of knowledge

Address correspondence to:
Prof. Dr. Ernst Pöppel ML
Human Science Center
Goethestr. 31, 80336 München
Phone: +4989218075650


Human knowledge expresses itself in three different modes, i.e. as explicit, semantic or verbal knowledge, as implicit, tacit or intuitive knowledge, and as visual, pictorial or episodic knowledge.

To refer to knowledge only as „explicit knowledge“ would neglect the other modes of knowledge that are of equal importance for higher cognition.

Unifying frames of the different modes of knowledge are the aesthetiic principle on a formal level and the mimetic principle on the level of reference.

1. Three modes of knowledge

How is intercultural communication possible? We speak different languages, we are embedded in different cultural traditions with different rituals, but still we believe to be able to communicate with each other and to understand each other.

It is believed that intercultural communication is based on a common denominator in cognition, and we claim that without such an common denominator being reflected in anthropological universals communication would be impossible.

It is our evolutionary heritage that provides a unifying frame (Darwin, 1872; Lorenz, 1943; Piaget, 1970; Poeppel and Hickok, 2004; Skinner, 1981; Tinbergen, 1956). From a logical point of view cultural specifics can only be discovered if they relate to a common frame within which such differences are expressed.

We believe that the common denominator is represented in different modes of knowledge that are shared by everybody, and perhaps not surprisingly these modes of knowledge have been recognized since antiquity.

The different cultural and religious traditions apparently independent of each other all have referred to explicit, implicit and pictorial knowledge as we like to refer  to these knowledge systems today.

The Christian bible in the King James version begins with the words: „In the beginning God created the heavens and earth. The earth was without form and void, and darkness was upon the face of the deep; and the Spirit of God was moving over the face of the waters.

And God said, „Let there be light“; and there was light. And God saw that the light was good; and God separated the light from the darkness. God called the light Day, and the darknes he called Night.“

This text from the genesis refers to three different modes of knowledge, i.e., explicit or verbal knowledge (saying, calling), implicit or action oriented knowledge (creating, doing), and visual or pictorial knowledge (seeing, recognizing). Similarly, Sura 96 of the Koran which is considered to be the first revelation of Mohammed refers to the act of creation, to pictorial knowledge (reading), and to the teaching of explicit knowledge.

And in the Chinese tradition we find a similar reference to different knowledge systems in Lun-yu II -18, when Confucius tells his student Zizhang how to get a higher position in the government: „Listen more, put aside those doubtful words and say the rest cautiously (explicit knowledge), then you will make fewer mistakes (action oriented knowledge).

Watch more (visual knowlege), put aside those perilous actions and do the rest carefully, then you will have less regret. With fewer mistakes in your words and less regret in your behavior, you are doing exactly what will bring you to what you want.“

The different bases of knowing are a consequence of how we process sensory information, how we feel or remember, how we make decisions or how we think. Although this manyfold basis of knowing is inherent to us, we have to remind ourselves of this fact; what is self-evident is easily overlooked.

Only after the self-evident is lost or damaged will it’s importance be recognized retrospectively. Effortless perception and action providing an adaptive advantage are primary goals of evolutionary selection (Mayr, 2001), and as a result of such selective processes self-evident activities like seeing a tree or saying a word occur without time-consuming reflection.

However, as these activities are self-evident, they remain in the background of attention (Bao and Pöppel, 2007). Self-evidence provides a frame of unquestioned confidence.

Only if after circumscribed injuries of the brain pictorial knowledge is shattered, voluntary movements have become impossible, or verbal communication is limited (Farah, 2000; Goldstein, 1944; Luria, 1973; Pöppel, 1989; Pöppel et al., 1973; Weiskrantz, 1986; Zihl et al., 1983), only then do we realize that such basic activities like categorizing and comparing, wanting and acting, seeing and talking, thinking and deciding, are gifts of nature.

When functional competence is disrupted attention is drawn to the self-evident, (if the neuronal machinery controlling attention is not itself affected), indicating that the unquestioned confidence in the operations of the mind is made available by a complex neuronal machinery (Nauta and Feirtag, 1986; von Steinbüchel and Pöppel, 1993). The loss of effortless processing is an indirect proof of the operative power of this machinery under normal circumstances.

How can the three modes of knowledge be characterized? We rather describe than define them, and although they are discussed separately, it should be kept in mind that in the normal brain’s activity they are interlinked; because of the architecture of the brain with its widespread projections no independence of any functional system can be assumed (Nauta and Feirtag, 1986; Pöppel et al., 1991).

The different modes of knowledge have to be understood within a frame of functional interdependence obeying the principle of complementarity (Pöppel, 2006), i.e. each system relies on the others.

2. Aspects of explicit knowledge

Explicit knowledge (EK) is information with meaning which usually can be expressed verbally (Baars, 1988; Cassirer, 1994; Pinker, 1994; Wittgenstein, 1921). EK is consciously available and it can be communicated using symbol systems like language (Graubard, 1988).

When EK is forgotten, it can be recovered from documents, i.e. EK is represented in an encyclopedia, in textbooks or nowadays in the internet. EK is accumulated by learning and this learning results in a corpus of semantic knowledge that one owns and that one can refer to in a distinct way.

EK is the kind of knowledge that has dominated Western culture during the last centuries, and many believe that whenever one refers to knowledge one only has EK in mind. An important historical example for EK is given by René Descartes with his „Discours de la Méthode“ (1637/1960).

In this discourse Descartes formulates four rules that should be applied if one is confronted with a complex situation: A problem has to be formulated clearly and distinctly (and one should approach the problem without prejudice and haste); a problem has to be reduced to a set of several limited problems, if it can not be solved as a whole; one should move from the simple to the more complex in proper order; and fourth, all aspects of the problem should be taken into account (the requirement of completeness).

These rules appear to be self-evident, and they are a necessary ingredient of human reasoning in science and beyond. What is hidden behind these apparently simple rules is, however, the unquestioned claim, that they in fact can be successfully applied.

The rationalistic program implies that it is possible to pose a question cearly and distinclty, to abstain from prejudices when solving a problem, to reduce a complex question to a full set of simpler ones, and to obey the law of completeness. These Cartesian rules exemplify the belief in the power of the human mind as represented in explicit knowledge.

Retrospectively, this approach has been extremely successful (Kuhn, 1962). Scientific discoveries are an expression of EK. The development of modern science would hardly have been possible if there would not have been a strong belief in rational conjecture; the fruits of thinking are scientific laws and on their basic technological developments (Bacon, 1620; Feynman, 1965; Helmholtz, 1896; Kant, 1781/1787) .

However, to believe that human knowledge is limited to EK may create some difficulties, even in science (Nietzsche, 1980). One example of some shortcomings if one trusts only in EK is the (short) history of artificial intelligence (Graubard, 1988). In the beginning, proponents of artificial intelligence (AI) believed that human knowledge in its entirety can be expressed in physical symbols, i.e. in an explicit form.

As an explicit representation can be expressed symbolically, it was thought that on such a basis algorithms can be developed that unambiguously mimic mental acts. As it turned out, however, it appeared to be impossible to transform human knowledge in it’s entirety into physical symbols; new developments take for instance embodied or tacit knowledge into account (Pfeifer and  Bongard, 2007).

Although it is in a way a caricature, EK can also be referred to with a neuronal metaphor as being mediated mainly by processing modules of the left cerebral hemisphere.

This picture is based on the observation that patients with injuries of the left hemisphere may lose their capacity to communicate EK; in particular lesions of the temporal lobe may result in the loss of semantic competence (Pinker, 1994) suggesting that the patients no longer command explicit knowledge.

Alternatively, one could argue that the brain of such patients can no longer link EK to a meaningful representation in language; some such patients report that their thoughts no longer find a way to words. Independent of these special problems one can, however, state that EK is selectively vulnerable.

What are the mental operations being necessary to create explicit knowledge? Presumably, EK is generated in a hierarchically organized system of neuronal operations beginning with categorization (Pöppel, 2006).

Any categorization takes place within a particular cognitive frame or reference system giving a semantic context; only if categories have been formed can they be related to each other, thus, allowing for instance comparison between them. A comparison can be made either with respect to quantitative or qualitative differences.

The notions of equality and inequality, identity and change, are necessary conditions for further operations like choice, selection or decision. These different operations of the neuro-cognitive machinery can be subsumed under the general process of abstraction which enables us to refer mentally to something in an explicit way.

What could be the purpose of explicit knowledge? It is suggested that this knowledge system is primarily used for the reduction of complexity of information allowing the construction of a corpus of valid semantic knowledge to be communicated to others in an effortless way.

Reduction of complexity becomes an issue, if one looks at the neuronal level of information processing; the different neuronal modules are confronted with the problem that afferent information is distributed both spatially and temporally in an unpredictable way.

Because of the transduction processes on the receptor level which introduce temporal indeterminacy of information within sensory channels, and because of the neuronal architecture of the afferent systems being characterized by a certain degree of projective divergence, neuronal information is rather ill-defined in central processing stages.

By a process of complexity reduction using for instance temporal integration windows (Chen, 2004; Mates et al., 1994; Pöppel, 1971, 2009; Pöppel et al, 1990;), and presumably by a complementary use of local and global features or bottom-up information and top-down schemata (Pöppel, 2006) some obstacles may be overcome to create explicit knowledge; this mode of knowing which is created in the past to be used in the future, can be made available to oneself or others using language or other forms of symbolic representation, like words or other signs. Using explicit markers communication is enhanced in speed, precision and efficiency.

3. Aspects of implicit knowledge

The second mode of knowing refers to implicit knowledge (IK), i.e. to what we can do without being able or not even wanting to explicitly indicate how or why we do something.

The difference between EK and IK might be characterized by two short statements, one going back to the Greek philosopher Socrates who explained while defending himself in court: „I know that I don’t know anything“.

With this statement he meant to say (according to our interpretation) that the corpus of his EK is extremely limited. Restating this sentence to characterize IK, one could say: „I do not know that I know“.

The fundamental difference between EK and IK can also be exemplified by a classical quotation from the writings of Augustinus who in the eleventh book of his „Confessiones“ writes: „Quid ergo est tempus? Si nemo ex me quaerat, scio; si quaerenti explicare velim, nescio“. („What then is time? If nobody asks me, I know it; if I want to explain it to somebody who asks me, I do not know it“.)

Here Augustinus uses the concept of knowledge within two different frames, at first as IK and then as EK. Thus, this rather famous statement from Western antiquity is poisoned with a categorical error, i.e. mixing two different frames of reference. (Actually, one can easily replace the word „time“ by other terms, like „space“, „consciousness“, „beauty“, „thinking“ or „knowledge“ and one can always give the same answer of knowing, but not knowing).

The categorical error is also true for the statement „I do not know that I know“; in this case EK and IK are also related to each other within different frames of reference, at first as EK, and then as IK.

The point we want to make here is not that it is rather easy to fall into the linguistic trap of a categorical error, but that the possibility to do so indicates that we easily connect different modes of knowledge, i.e. EK and IK, without being aware of the fact that they belong to different frames of reference.

Implicit knowledge comprises not only intuitions that remain silent, i.e. that lack a verbal representation, but it refers also to bodily knowledge like movement patterns or sequential acts that are beyond explicit monitoring like playing a musical instrument, hitting a golf ball or driving a car. Expertise in such cases means that conscious control is no longer required at every instant.

Procedures can become automatized, and during action it is impossible to indicate in detail, how something is done, and which components have to be integrated for a complex movement to be smooth or an act to be efficient. Retrospectively, it may be possible to appreciate the instantiation of such kind of IK as having been successful; if a movement pattern was imperfect, or an action was interrrupted, IK can more easily be subjected to an explicit analysis.

An expression of IK is also ritualized knowledge that characterizes daily activities. From morning to evening, and throughout weeks, months and years we are embedded in repeating frames of activities and duties which are never questioned, and which become only apparent when there is a change.

Ritualized IK defines our meals, the sequential duties of our work, the time frame of holidays, or symbolic behaviour in religious services (Eibl-Eibesfeldt, 1995). We would like to submit that ritualized IK leads to the feeling of security as repeating sequences of events result in habit formation (Helson, 1964).

The adaptation to the sequential structure of socially or self-defined events creates a reliable time structure that reduces mental work load and, thus, allows effortless behaviour. The functional goal of habituation is to remove regular events as carrying redundant information from the focus of attention (Baars, 1988).

A special form of ritualized IK are prejudices which can be looked at not only as mindless behaviour but primarily as an expression of complexity reduction within the social domain allowing fast judgment about others in an economical way (Darwin, 1872).Representatives of another group are tagged with a specific mental category which simulates quick information.

As any percept or thought operation happens within a frame or reference system which usually remain mute to the observer or thinker, everybody is vulnerable to prejudices (Pöppel, 2006). Again, only retrospectively do we sometimes realize having fallen into a trap of bad judgment.

Although prejudices are a negative example, we would like to claim that most human activities are in a positive sense an expression of implicit knowledge. We are much less rational as we are inclined to believe about ourselves.

The philosopher Friedrich Nietzsche once remarked (in:„Jenseits von Gut und Böse“ – Beyond Good and Evil), that it is impossible to accept the statement of René Descartes: „Cogito ergo sum“ – „I think therefore I am“.

The most one could say would be: „It thinks“, and even this may be too much. Thinking is rather an implicit process and occasionally a result of this process may surface, and this may be experienced for what the Greek mathematician Archimedes is known for after having discovered the principle of the specific gravity (relative density) sitting in his bath-tub: „Heureka“- „I have found it“, the expression of a sudden insight.

What one refers to as intuition is also an expression of implicit knowledge. Critical tasks of the mental machinery like decisions are often (or usually) made without an explicit represenation of all necessary variables that should be taken into account.

Decisions are usually embedded within an emotional frame, although this frame might not necessarily be explicitly represented when a decision is made.

Intuitive or IK is, however, not irrational (with the exception perhaps of certain prejudices), because retrospectively it is possible to analyze within a rational frame whether a decision made sense, and as it happens intuitive decisions are not known to be worse than others.

In fact, it is impossible to make a decision on a merely explicit basis as too many intervening variables in a decision process play a role that remain in the attentional background.

The richness of IK is unfortunately (or fortunately) beyond computability; there are too many factors one would have to consider to compute potential states of implicit knowledge.

If we assume only 100 different modules in the brain, either being active or inactive, such a brain would have already 10 to the 30 potential brain states, if one accepts the premise that any functional state is implemented by a spatio-temporal pattern of modular activities (Fodor, 1983).

Most likely there are more modules which characterize mental activities, and taking only two different modular states is a rather conservative guess; this means that from a computational point of view any individual brain at any instance is characterized by a unique neuronal pattern.

Thus, because of the large number of brain states which are beyond computability, the output of the brain as reflected in experience or behaviour in detail is unpredictable.

Using an image, IK can be seen as an ocean with invisible activities under the surface; sometimes the surface is penetrated from below and an island is formed apparently giving (or simulating) a stable landmark.In this image islands represent explicit knowledge which can be made communicable, and it is the functional complementarity of IK and EK that characterizes the neuro-cognitive machinery.

Implicit knowledge as a special functional domain can be conceptually also derived from observations obtained with brain-injured patients (Luria, 1973; Pinker, 1994; Teuber, 1960; Tulving 2002).

After a special lesion, a patient may report being blind for some areas in the visual field. Asking the patient whether he recognizes something he will report that he cannot see anything. But still, there is some residual vision (Pöppel et al., 1973).

He can process visual information for instance with respect to where something is, without being able te explicitly reporting „seeing“ an object. Some patients can discriminate simple patterns without having consciously (or verbally) access to their successful performance.

A special form of this paradoxical ability has been called „blindsight“ (Weiskrantz, 1986), which indicates that EK and IK can be dissociated. Apparently the human brain even on a very high level of information processing can do things that remain mute, and that traditionally have been associated with conscious representations.

Describing the different aspects of IK, it becomes clear that IK itself is not a homogeneous knowledge system, but that we have to deal with several, at least two sub-systems.

On the one hand IK refers to implicit cognitive processes whose results sometimes come to a surface being subjectively represented as an insight or a decision; on the other hand IK refers to bodily knowledge as reflected in movements or behavioural sequences.

A movement can be either expressed in simple or complex trajectories which usually are acquired by sensorimotor learning; or it can be expressed in behavioural sequences that often are ritualized.

With respect to the purpose of IK, we would like to suggest that in all its manifestations it serves the goal to allow fast action, to implement quick decisions, to reduce mental workload, and to provide a feeling of security and trust in one’s behaviour.

4. Aspects of pictorial knowledge

The third mode of knowing is pictorial or visual knowledge (PK), and PK itself can be subdivided into different domains, like sensory knowledge (Kohler, 1951; Zeki, 1999) within the subjective present („present PK“), mnemonic PK as it is represented in episodic memory (Tulving, 2002), and topological PK (Chen, 2004) as it is seen in geometric figures, visual models, diagrams or histograms, and that allows the construction of maps being used for instance in navigation.

4.1 Present pictorial knowledge

It may come as a surprise to refer to visual perception proper as „knowledge“, but we follow here both a tradition going back to Greek antiquity, namely that „aisthesis“ not only means perception, but also knowledge or understanding, and an argument by Zeki (1999); he writes (p. 8): „The pre-eminent function of the visual brain is the acquisition of knowledge about the world around us.“

The reason why we tend to forget that seeing is knowing depends perhaps on the fact that present VK is so self-evident that it’s importance is only realized when it is lost or when certain attributes of visual experience are altered;

the loss of colour or movement perception, the inability to move around in one’s own environment, or the reduction of foveal sensitivity after macular degeneration make realize that the effortless access to knowledge in the world around us has been disrupted.

When we open our eyes or when we are exposed to a complex new stimulus experimentally, visual knowledge is accumulated in much less than a second (Boring, 1933).

Although on a pre-semantic level, i.e. if we look at the projected image on the retina, we merely are exposed to visual surfaces and edges, it is hard to convince ourselves that this should already be „seeing“.

Our visual brain creates instantaneously perceptual objects; apparently, we are forced to always see „something“, and when the „something“ does not make sense because it is geometrically impossible (as in some pictures of the Dutch artist Escher), we attribute meaning.

It is impossible to see the impossible. Presumably using complementary mechanisms (Pöppel, 2006) visual percepts are constructed binding topological invariants (Chen, 2004) with local features from the afferent channel.

The construction of the visual word is an effortless process, and what is perceived is taken to be true; this latter statement can be more easily expressed in German, as perception („Wahrnehmung“) is related to truth („Wahrheit“); what we perceive („wahrnehmen“) we take as being true („für wahr nehmen“). Thus, seeing is knowing.

That present PK is a separate mode of knowing can be shown if one looks at patients with visual agnosia, who still may have a rather intact peripheral visual system, but who cannot make sense out of what they are seeing (Farah, 2000; Goldstein, 1944; Teuber, 1960).

A special case of agnosia is the difficulty to recognize different human faces. Apparently, the human brain is endowed with a neuronal module that enables us to effortlessly identify persons. In prosopagnosia this self-evident capacity is lost; such patients can still see a face as a face, but they are unable to identify a special person using distinct facial features.

If such patients want to recognize somebody, they have to use other means like the voice or certain attributes (like the colour of the hair). The observation that there may be a dissociation between the recognition of „faceness“ in general and individual faces may be of philosophical interest.

We would like to conclude from this surprising dissociation, that a special neuronal module represents a general scheme of faces. Under normal circumstances this scheme is complemented by local visual information to allow the perceptual construction and, thus, the identification of an individual face.

In prosopagnosia the local information is no longer available or (more likely) it can no longer be attached to the spared scheme, thus, leaving the representation of the general scheme empty.

Philosophically speaking such a scheme may correspond to the Platonic ideal, and the special lesion allows us to look not only into the neuronal machinery of visual perception, but also empirically into the components of an epistemological theory.

This applies also to a statement by Immanuel Kant from the „Critique of Pure Reason“: „Gedanken ohne Inhalt sind leer, Anschauungen ohne Begriffe sind blind“ (Thoughts without content are empty, percepts without notions are blind). Rephrasing the Kantian sentence one could say that schemata without content (i.e. sensory information) are empty, and sensations without schemata are blind.
4.2 Mnemonic pictorial knowledge

Whereas present PK obviously refers to any given moment, mnemonic PK is anchored in the past. Certain episodes that have some personal relevance can be stored in memory, and it is an important feature of episodic memory that only one exposure to an event leads to long-term storage (Tulving, 2002);

this feature of „one-trial-learning“ separates episodic memory from semantic memory which is built up with much more time-consuming effort.

The images in episodic memory are preferentially (but not always) stationary pictures, they always are related to a specific place, and the episode that led to imprinting had a high emotional impact. If one analyses these pictures from the past (unpublished observations from several hundred observers), one is surprised how small the number of images is that can be actively brought into working memory, i.e. into the subjective present. Independent of age or sex it is on average only 10 to 30 images that can actively be remembered from the past day.

If one asks how many images can be evoked from the previous week leaving out the previous day, it is approximately the same number. This observation implies that images in episodic memory have a rather short half-life, and that presumably only those with high personal importance are stored for a life-time.

On average it is only a few hundred images in our episodic memory we can refer to. It should be noted that these images are actively remembered; the number of images that can be recognized is much higher. This poses the question why the „inner museum“ of humans should be so limited.

One reason might be that personal images from the past are essential elements for the definition of personal identity. Only such images are maintained (like in a real museum) that are significant, and which allow a personal anchoring in one’s own past.

As Tulving (2002) has pointed out, we can do some time traveling going back into our personal history. This time traveling goes only to relevant events to the past and may support our self-identity, as a visit to the museum assures cultural identity.

There is another aspect about images in episodic memory that should be noted, i.e. that such images undergo surprising changes. Some observers report that when visualizing the same image on successive days, thus, having a longer temporal interval between the imprinting of the image and the reactivated image, contours of persons or objects become less precise; they seem to fade away.

This observation would imply that images are represented in a topologically organized way as pictures, and it would suggest furthermore that basic neuronal processes like lateral inhibition which characterize normal vision (Ratliff, 1965) also operate on a stored image; the gradual fading of precise contours indicates the operation of a neuronal process being equivalent or perhaps even identical to lateral inhibition in normal vision.

Images from the past are usually colored although with less hue, and they always are visualized in front of oneself, i.e.centered around the visual axis; the periphery of the visual field is hardly represented in episodic memory.

This observation implies that mnemonic VK is person-centered, i.e. images are not stored with respect to an external coordinate system what in principle also might have been possible.
4.3 Topological pictorial knowledge

Topological PK is qualitatively different from present or mnemonic PK; whereas the latter refer to natural images past or present, topological PK is based on abstractions as they are expressed in geometrical figures, or as they visualize observations in diagrams or models.

Prior to the two-dimensional or three-dimensional concepts as developed in Euclidian geometry, a fundamental abstraction was necessary, i.e.,  the „discovery“ of the line and the point.

As real objects in visual perception are created only by edges and surfaces, the abstract idea of a line or a point had to be conceived which together with the concepts of a surface and a body are fundamental for geometrical reasoning. Topological PK as expressed in geometry made itself independent of real objects.

Visual representations of geometric PK all are aesthetically pleasing like the conic sections allowing the construction of a circle, an ellipse, a parabola or a hyperbola.

Similarly, squares, rectangles, in particular those that use the golden section as a constructive principle, symmetric triangles, or helical spirals carry an intrinsic aesthetic pleasure perhaps because of their simplicity and apparent order.

With the advent of analytical geometry it became possible to visualize complex processes as expressed in mathematical formula in a simple way like growth functions.

The sigmoid curve in all it’s simplicity characterizes phase transitions in all domains of scientific discourse like in psychology, if one looks at learning curves, or in chemistry if one studies the time course of chemical reactions;

any transition between qualitatively different states shows a sigmoid characteristics, and the visualization of these transitions indicates that in spite of a rather different material basis of these processes the operational logic is similar or even identical. Topological VK allows a fast insight into an otherwise complex data generating mechanism.

Statistical distributions are typical expressions of data generating mechanims. When measurements are collected, the specific form of a histogram showing how the single data points are distributed gives a first and important cue;

a Gaussian distribution allows a judgment about the structure of the data and suggests the selection of statistical tools to be used for further analysis. A bimodal or multimodal distribution indicates that the data generating process is not homogeneous; outlying observations that destroy the symmetry of a distribution, sometimes carry unexpected information that can be creatively harvested (Pöppel, 1970).

Visualizations of correlations or the representation of functional dependencies in a diagrammatic form again use the effortless availability of a visual percept for judgment.

A further domain of topological PK refers to models and maps like the visual model of the planetary system, models in physics (like Bohr’s model of the atom), chemistry (like visual models in chemical bonding) or biology (like the visualization of evolution as a tree).

In each case reality is radically simplified using specific abstractions suggested by theory for the construction of a pictorial representation. The driving force behind the desire to express knowledge in a visual way is a special feature of the visual system, i.e. to allow access to information in an effortless way.

Thus, pictorial representations to create  topological PK  are automatically created in such a way to comply optimally with the processing of the visual system. If this line of argument is accepted it follows that the adaptation of such models to the features of the „visual frame“ leads to a limited view of the original fact or even to misrepresentations. Any visual model is necessarily a caricature.

5. The aesthetic and the mimetic principle: Unifying concepts of knowledge

5.1 The aesthetic principle

At first we would like to have a look at the perceptual or aesthetic principle (Baumgarten, 1750 / 1758) which is considered to be essential in the arts like unity or completeness of what is represented, order or the relation of the parts to the entire gestalt, harmony or rhythm for temporal patterns, and simplicity and effortless access to a picture, a melody or a verse (at least within some theoretical frames).

It was the Roman poet Horatius who more than two thousand years ago called for the “simplex et unum” in the arts (in “De Arte Poetica”), i.e. that there must be unity and congruence between what is perceived in a piece of art and what has been previously experienced by the person. A mismatch between present perception and a frame of knowledge built up in the past would be an indicator of bad quality or a challenge to define a new frame as has been demonstrated many times in art history.

What are aesthetic principles that characterize knowledge, and that similarly apply to the arts? We would like to refer to explicit knowledge following again the analysis of Descartes in his “Discours de la Méthode” (see above).

Descartes stresses that clarity and precision of a percept or a thought are essential; order has to be recognized or created if necessary; a problem has to be appreciated in its entirety, i.e. as a unity.

Furthermore, explicit knowledge is characterized by simplicity, and scientific laws gain easier acceptance, if they provoke some aesthetic pleasure, the latter even being sometimes used as a criterium for truth. Although it may be a metaphysical statement, we trust in “Occam’s razor”, i.e. that the simplest explanation is believed to be the best explanation.

Simplicity and clarity of explicit knowledge are also necessary elements for effortless communication; to reach other people in an efficient way knowledge has to be transferred reliably, and as communication should be fast if we take an evolutionary point of view, the content of what is communicated has to be precise.

Taken together, the attributes that characterize explicit knowledge like clarity, order, unity or simplicity are the same attributes that are considered to be unifying principles of aesthetics. As communication in the explicit mode depends on these principles, it follows that social cohesion also depends on the aesthetic principle.

Thus, the concept for instance of unity is both fundamental for knowledge and the arts. However, unity is a self-evident phenomenon that becomes enigmatic only if it is lost. Goldstein (1944) for instance considered the fundamental disorder caused by damage to the frontal lobe to be the inability to grasp the entirety of a complex situation.

Patients with such lesions show a difficulty to keep two things in mind; they can focus only on separate aspect of a story, and have difficulties in understanding a story as a whole. Equivalent observations have been made by Luria (1973) with a rather simple test.

His tapping test requires to remember two rules: The patient has to tap once when the experimenter taps twice, and he has to tap twice when the experimenter taps once; during the test the patient has to inhibit the tendency to mimic what the experimenter is doing. Both young children and frontal lobe patients have severe difficulties to perform the task successfully.

These observations indicate that the creation of unity is an active mechanism of the human brain which may be disrupted selectively. Similarly, other brain lesions may result in a difficulty to recognize or create order, or to allow abstraction of processed information.

As the basic attributes of knowledge are vulnerable, they must reflect intrinsic mechanisms of how the brain procesess information; thus, aesthetic principles cannot be constructed in a normative way, but they follow rules defined by neuronal mechanisms. 

Similar aesthetic principles as identified for explicit knowledge are also characteristic for the other modes of knowledge. Present pictorial knowledge has been said to function effortlessly; schemata are necessary to recognize for instance a face, and such schemata are simple. The perceptual process creates “something” (a visual image), which is just “one” image, i.e. the percept within this “inner theatre” is characterized by unity.

The percept can be conceived of appearing within a frame; as the percept is always just one, the surround beyond the focus of attention simulates a physical frame. But there is also an abstract frame: In this latter sense every percept is generated within a frame of expectation; every percept is the verification or falsification of an hypothesis in a given moment (Pöppel, 2006). Without a top-down component complemented by bottom-up sensory information pictorial knowledge would be empty.

The relevance of frames or personal reference systems and the aesthetic principle of unity are also true for mnemonic pictorial knowledge; only images that have some personal meaning are stored within our “inner museum”; these singular images from the past which had some emotional impact when they were imprinted (and which always refer to a specific place) represent our personal history and define our identity;

if these images are lost, we lose ourselves. As most images in our episodic memory represent other people, mnemonic pictorial knowledge is also instrumental to create a social bridge from the past to the present, and from the present to the future. Mnemonic pictorial knowledge is fundamental for the development of the notion of time;

we can intentionally travel backwards in time to visit our “inner museum”, and we can construct on this basis the notion of a future and define a present. This conception of a linear time again is characterized by aesthetic principles, i.e. simplicity and unity; time is conceived of being unidimensional and time is homogeneous “that flows equably without relation to anything external” (as Newton states in his Principia Mathematica Philosophiae Universalis; for an alternative view see: Ruhnau and Pöppel, 1991).

The aesthetic principles of simplicity and unity also apply to topological pictorial knowledge. A visual representation of a relationship as expressed for instance in a sigmoid curve or a Gaussian distribution allows an effortless access to a corpus of data that may represent a complex functional system.

Symmetries and deviations from symmetries give insight into data-generating mechanisms. The sensitivity of the visual system to detect mirror-symmetries makes the system in particular useful to detect deviations from symmetries which often provoke new scientific insights.

Thus, this aesthetic principle can even be used as a research tool. Topological pictorial knowledge expresses abstracted knowledge which implies that a process of abstraction must precede the visual representation itself. From this necessary sequence of mental operations one can conclude that the process of abstraction intrinsically follows aesthetic principles. What is abstracted, complies already with our sense of beauty.

For the aesthetic principle that is characteristic for implicit knowledge, we would like to refer to the reafference principle (von Holst and Mittelstaedt, 1950), as this principle may provide an additional cue for a unifying principle. In the original form the reafference principle expresses the following idea: Any movement is regulated both by an efferent command to the effectors, as well as by a copy of this command (the “efference copy”);

when the movement is finished, reafferent information from periphereal sense organs is compared with the efference copy. If the reafference matches the efference copy, the movement has been successfully completed. Thus, the comparison of efferent commands and reafferent signals allows a monitoring of bodily states which results in perceptual stability, and as Teuber (1960) has pointed out, in perceptual identification.

A generalized reafference principle (GRP) can be used as a theoretical frame not only for simple movements or percepts, but for actions in general, i.e. for instantiations of implicit knowledge. Any act and any action following an explicit or implicit command or plan are neuronally controlled by efferent signals to the effector organs and efferent copies stored centrally.

Efferent copies of intended acts and actions allow a continuous monitoring; a mismatch between the copy of the intention and the reafferent information tells the system, that act or action are not yet completed. However, if the reafference corresponds to the efference copy, an act or an action has been brought to an end.

The basic idea of the GRP is that it operates independently of a particular time window. The GRP can explain short term control of movements like eye movements, it applies to ritualized movement or actions of a longer duration, and it refers to long-term plans that may take days, weeks or months (or even longer) to be completed.

Thus, the GRP represents an endogenous monitoring system indicating the completion of acts and actions. The subjective impression of fulfilment or satisfaction after having made a movement or after having reached a goal is the result of the final comparison of reafference and efference copy.

We would like to suggest that the feeling of unity of a movement after its completion can be understood using the operative mechanisms of the generalized reafference principle.

A host of human activities is characterized by the wish to be satisfied by the gestalt of a movement or a performance like hitting a golf ball, sailing a boat, playing a musical instrument, or giving a talk.

Satisfaction about the intended gestalt is a retrospective experience of unity. Thus, the striving for unity in acts and actions and the (occasional) accomplishment of such unity indicates, that also in the domain of implicit knowledge as it is instantiated in the control of movements or in the organization of complex behavioural sequences obeys the aesthetic principle.

Taken together the following aesthetic (or perceptual) principles have been identified as attributes both for the arts and the different modes of knowledge, and as has become apparent, these principles have been formulated already during antiquity and they have been reiterated since then. To exemplify the aesthetic principles in a concrete way, one can imagine being in different situations (as an internal point of view is both more satisfying and convincing):

Watching a bird in the sky, hitting successfully a golfball, remembering a verse from Shakespeare (“Shall I compare thee to a summer’s day”), activating an episode of love from memory, being surprised by a sudden understanding of experimental data, looking at a portrait from Rembrandt, giving a lecture to students, having a meal with friends, hearing the Tristan motif by Wagner –

for all these activities that refer to the arts, to perceiving, acting or knowing, there is (in the ideal case) unity of experience and the impression of completeness, there is simplicity as a successful reduction of complexity, there is clarity of a thought suggesting reliability and precision, there is order with a proper relation of the parts to the whole, there are rhythm and harmony triggering satisfaction, and there are conceptual and emotional frames defining meaning of what is experienced and creating an atmosphere of affiliation and empathy.

If these attributes of knowledge or the arts are missing, sometimes because of a lack of one’s own concentration and sometimes because of bad quality, a feeling of frustration, of anger, or of incompetence may be the consequence which are important signals indicating that the aesthetic principle has been violated.

5.2 The mimetic principle

We believe that the driving force to establish knowledge is “mimesis”, i.e. the internalization of regularities by imitation. Thus, knowledge is basically a copy, a view which in the tradition of psychology has first been expressed in psychophysics by Fechner (1860), i.e. that mental representations represent physically definable and defined situations (Boring, 1933; Helson, 1964; Stevens, 1986).

A similar view is for instance taken by Piaget (1970 ) or by Eibl-Eibesfeldt (1989) on the basis of observations made with children or looking at the developmental function of playing. At early phases of human development in a playful way knowledge is acquired by imitation and repetition.

Thus, mimesis in a general sense results in the ownership of knowledge, i.e. knowing is owning.

What can we own? In visual knowledge the world around us is represented retinotopically in our visual brain; representation “copies” the world around us, i.e. mimesis creates some match between the physical world and a “copy” of this world in our brain.

But this “copy” is not a passive and mirror-like representation, but the physical world around us (“Realität” in German) is actively incorporated into our cognitive machinery resulting in a subjectively meaningful representation of reality (“Wirklichkeit” in German). Thus, one has to distinguish between two meanings of “reality”, one referring to the physically described world around us, and one referring to the subjctive representation of this world, the latter being correlated with the physical world, but not being an image like a photograph.

A corresponding doubling of the world applies to mnemonic visual knowledge, as we carry with us the images of the past. In the case of mnemonic visual knowledge mimesis is more selective, keeping only such scenes in our memory that prove to be of long-term significance and are essential for the maintenance of our identity; we are a copy of our past.

In topological visual knowledge mimesis is embedded in a process of abstraction leading to a lawful representation of a partial set of reality. Laws mimic regularities that we observe in the physical world. Furthermore, the mimetic principle also applies to implicit knowledge; any act or any action is the instantiation of an intention or a plan, and the mimetic drive reates a copy from a central matrix in our brain and transfers this copy into action.

Finally, explicit knowledge represents facts about the world. Representation even on the abstract level is necessarily a copy, and the process of copying is the consequence of the underlying drive to create knowledge by mimesis.

Coming back to intercultural communication and cognition we would like to submit that because of our evolutionary heritage we all share the same modes of knowledge and their unifying principles. They provide a common frame,

but within this common frame cultural and individual specifics are expressed which make us different. If we ask ourselves “what it means to be human” we would like to conclude that we enter the world with genetic programs of possibilities which are common to everybody,

but that cultural and individual environments result in a selection of specific neuronal programs by processes of imprinting as has been shown by ethological analyses of human behavior (Eibl-Eibesfeldt, 1995). Thus, culture determines structural selections of neuronal processes, i.e. culture becomes structure of the brain.

However, these selections by imprinting can happen only within limits; basic principles of neuronal processing of the cognitive machinery are conservative and remain robust against changes that would move human behavior too far away from “how we are meant to be”.