Ernst Pöppel (August 2024)

A categorical problem in the “Transcendental Aesthetic,…Metaphysical Exposition of the Concept of Time” and a way out with “complementarity as a generative principle”

Immanuel Kant begins this section in the „Critique of Pure Reason“ with the words: „Die Zeit ist kein empirischer Begriff, der irgend von einer Erfahrung abgezogen worden. Denn das Zugleichsein oder Aufeinanderfolgen würde selbst nicht in die Wahrnehmung kommen, wenn die Vorstellung der Zeit nicht a priori zum Grunde läge.“ Translation by Norman Kemp Smith (1929): „ Time is not an empirical concept that has been derived from any experience. For neither coexistence nor succession would ever come within our perception, if the representation of time were not presupposed as underlying them a priori.” Although the translation is not quite convincing it indicates like in the original German a categorical problem: It is implied that “coexistence” (or “simultaneity”) and “succession” are on the same categorical level. In my view this is incorrect. 

The term “succession” refers to the perception of events which have to be detected as distinct and separate entities; this takes place on the level of phenomenal experiences reflecting temporal order. The term “coexistence or simultaneity” indicates an abstraction; if perceptual phenomena are not experienced as successive, it is mentally derived or implicitly constructed that they have been simultaneous. If events would be experienced as coexistent or simultaneous one would have to assume that we own two conscious parallel streams of information processing; this contradicts even common sense. The direct experience of simultaneity is impossible. In the Kantian statement we are dealing with a retrospective construction (simultaneity) and a present experience (succession); these two different mechanisms in the cognitive machinery are characteristic for the temporal organization in the brain. 

This leads to the question how neural systems in the human brain are operating with respect to temporal information, in particular whether information processing is continuous or discrete. The sense organs operate like antenna to collect information from the physical environment. The temporal availability of information in the perceptual systems in the sense organs like hearing or seeing is different because of biological features of the sense organs, namely different transduction times and the anatomical representation of information in the brain with substantial divergence of projection from the periphery to centers of the brain; thus, stimuli are ill-defined. The way out of this problem (as a consequence of our evolutionary heritage) is that temporally discrete processing units (presumably based on neural oscillations) are implemented. The trick of “mother nature” is to leave the physical continuity of time behind (as conceived of in classical or Einsteinian physics) and to create time windows within which the perception of temporal succession is give up; physically successive information is treated in these neural system states as co-temporal which means in fact a-temporal. Experimental evidence shows that the minimal time to create perceptual events in these time windows of several sensory modalities (vision, audition, touch) is some 30 milliseconds. These events are the “cognitive material” as operational basis for the experience of succession. 

Given such cognitive material, further stages on another processing level are initiated which can be connected to another famous statement in the Kantian critique: “Gedanken ohne Inhalt sind leer, Anschauungen ohne Begriffe sind blind”.   (Thoughts without content are void/empty; intuitions without conceptions/concepts are blind.) One is invited with this statement to introduce the concept of “complementarity as a generative principle”. Content experienced as successive events are necessary, but they are not sufficient to create a “state of being conscious”; pre-semantic temporal frames or time windows are necessary, and they are implemented on another processing level. It has to be stressed that “complementarity” is understood in this case as a generative or a creative principle and not (like in quantum mechanics) as a “descriptive principle”. 

What is the evidence from the point of view of cognitive science for complementarity as a generative principle? It is claimed that the cognitive machinery and reflections about cognitive representations can only be explained appropriately if one gives up monocausal explanations. One has to step out of the straitjacket of Occam’s razor (“entia praeter necessitatem non sunt multiplicanda”). Searching for the most simple explanation of cognitive phenomena and their implementation in neural systems is like a dogma, (and this applies to the sciences in general). The sentence “nihil est sine ratione” (nothing is without reason) is usually understood as “nothing is without ONE reason”, i.e. it is understood within a monocausal frame. One may even call this explanatory attitude as “monocausalitis”, a disease that many humans (if not all) have become victims presumably because of our evolutionary heritage; we want to make everything simple presumably to be fast in judgments and decisions. Albert Einstein apparently once said: Make it simple, but not too simple. Here a few examples are given that indicate complementarity as a necessary concept for understanding human cognition and rejecting too simple explanations. These examples are given just in a nutshell; they are based on numerous empirical observations, experimental data and conceptual analyses.

Humans like other higher mammals enter the world at birth with genetic possibilities. These possibilities provide some openness for imprinting in the natural and cultural environment. The “nature-nurture-conflict” is actually not a conflict but a necessity. As organisms like humans on this level of complexity cannot be preprogrammed because specific environments cannot be anticipated, “mother nature” uses complementary of both genetic endowment and environmental parameters to “create” a functional cognitive machinery. After imprinting it actually does not make sense whether it is “nature” or “nurture”; the two complementary parts have been blended or unified.   

Another example is directly related to the famous Kantian statement “Thoughts without content are empty; intuitions without concepts are blind”. In the language of brain systems we talk about “bottom-up” and “top-down” processes. Whenever the sensory systems process information from the external world in the different modalities (seeing, hearing, touching, tasting or smelling) this bottom-up material in pre-semantic neural pathways reaches further processing stages which represent the information within a semantic frame.  “Intuitions” become meaningful within a frame of “thoughts”, usually guided by the attentional control mechanisms. Thus, the statement of Kant has become a basis of modern cognitive science.

As indicated above, the brain is characterized by “time windows” within which information is integrated. One such prominent time window as indicated has a duration of some 3 seconds; this time window can be considered as an operative basis of the “subjective present”.  There is ample evidence about the existence of this time window derived from ethological observations, experimental data, measurements on neural activities. What could be the reason for such a temporal phenomenon?  One crucial task for the brain is to create the identity of something as something, and the time window of some 3 seconds seems to be the operative basis for identity creation and identity maintenance. This maintenance has, however, a temporal limit; after some 3 seconds “the brain asks” what is new? The mental content is either confirmed or a new content enters the subjective present. Thus, identity of a percept or a concept reflects stationarity, the control whether something has happened or not reflects the dynamics of the cognitive machinery. Stationarity and dynamics are  complementary aspect of cognition. Coming back to the initial statement of Immanuel Kant it can be stated that on an abstract level succession and simultaneity are complementary indicating basic principes of human cognition. Furthermore,  we have to deal with another conceptual complementarity, namely the notion of continuous time in classical physics and time windows as necessary logistic functions of human information processing.