Interdisciplinary Approaches to Neuroscience

0 downloads 0 Views 446KB Size Report
Sep 30, 2012 - Tobias Alecio Mattei ... synthetic knowledge according to Kant's definition. ... Such standardization has the purpose to provide a better level of comprehension as well as ... from sight, hearing or touch. However .... never offers by itself direct information as if it was a copy of the object, as logical positivists.
Interdisciplinary Approaches Epistemology and Cognition

to

Neuroscience

September 30, 2012 | ISBN-10: 1619422735 | ISBN-13: 978-1619422735 | Edition: 1 Nova Science Publishers Inc/New York - (September 30, 2012)

Editor: Tobias A. Mattei, MD

HTTP://WWW.AMAZON.COM/INTERDISCIPLINARY-APPROACHES-NEUROSCIENCEEPISTEMOLOGYCOGNITION/DP/1619422735/REF=SR_1_1?IE=UTF8&QID=1376603809&SR=81&KEYWORDS=MATTEI+TOBIAS

CHAPTER 2:

THE ‘ANTIQUE’ AND THE ‘MODERN’: NEUROSCIENTIFIC REMARKS ON KANT’S EPISTEMOLOGY OF SPACE Tobias Alecio Mattei Neurosurgery Department - University of Illinois at Peoria/IL - USA

2

Tobias Alecio Mattei

ABSTRACT This exposition intends to demonstrate that Geometric Knowledge is a kind of synthetic knowledge according to Kant’s definition. We emphasize the presence of an “a priori” component in this knowledge, apart of its most evident empirical portion. Initially we discuss Kant’s concepts of “a priori”, empiric, synthetic and analytical. In the sequence we expose our arguments in favor of the presence of a synthetic and “a priori” component in Geometric Knowledge. This discussion will be based on current empirical evidence from both neuroanatomy and neurophysiology. This approach will provide us insights about the way geometric forms are integrated in the human minds, form afferent sensory pathways up to multimodal association areas of the cerebral cortex (especially the right posterior parietal cortex) responsible for synthesis of these primary sensorial data in a consistent whole to be presented to human consciousness. Our final objective is to relate some parts of this cognitive process with Kant’s concepts about Geometry, corroborating, this way, his philosophic statements with empirical evidence from neuroscience.

1. INTRODUCTION “The possibilities of sensorial Inputs interpretations are based in our inborn dispositions, which derive from genetic instructions for the construction of the brain” John Eccles [1974] “There is no human experience, and no experience is possible, without subjective availability... it consists in an inborn psychic structure which is the factor that allows men to build and live this experience” Carl G. Jung [1928]

2. DEFINITIONS Initially, it is important to define some concepts that will be used along this exposition. Such standardization has the purpose to provide a better level of comprehension as well as more consistency to the presented arguments. These conceptual definitions are very important, since confusion among the terms applied in this essay may alter significantly the understanding of the presented ideas. (An example of this would be the confusion of what we call “Geometrical Knowledge” with the concept of “Geometry” used when someone speaks, for example, of Euclidian or Non-Euclidian Geometries.)

2.1. Spatial Perception Spatial Perception is the phenomenological representation in the human mind of aspects related to position and spatial relations among objects of the real world. Here we are not discussing Geometry as “numenum” (In Kant’s definition as a ‘thing in itself’) but rather as a geometric ‘phenomenon’ (in other words as the way geometric forms presents itself to the consciousness).

The Antique and the Modern

3

2.2. Spatial Imagination Although one source of bringing geometric relations to the mind is the experience (Spatial Perception), one can easily see that this is not the only way. When someone imagines, he is also capable of thinking geometrical and spatial relations, even if these elements do not have any component derived from experience. As stated by Aristotle: “The Imagination is the reproduction of the sensation without the presence of the sensible object” [1]. Here someone might raise the objection that, when someone imagine, what he are doing is bringing the special aspects of previous experiences from his memory. We would like to demonstrate, through an example, that, even though the basis of imagination can be a previous experience stored in memory, this fact is not necessarily true for all the events of imagination. Of course someone can, using memory, imagine something that is supposed to be similar to a perception of a scene that occurred some time ago. I say similar, because the essence of imagination is the lack of exactness and clarity, in opposition to perception itself, which is concrete, clear and exact. However, let’s imagine someone who is born blind. Certainly this person has not had any previous visual experience. However, this person can certainly form images with some spatial content in his mind. To prove this fact, we can ask such blind person to draw in a paper some geometrical form which presents to his thought. Probably we would be able to observe a figure with spatial characteristics similar to those experienced by anyone else. The fact that this person never had any spatial character experiences does not suppress his natural capacity of thinking spatial relations. It is worth emphasizing that that both Spatial Perception and Spatial Imagination are ‘phenomenons’ of consciousness; in other words, they occur in a specific instant to a specific subject. They are both personal mental processes which occurrs in a specific point of time.

2.3. Spatial Cognition The Spatial Cognition corresponds to the capacity of an individual to perceive spatial relations among objects as well as to deal with notions of depth, solidity and distance. This capacity is specially mediated by a specific region of the human cortex, the posterior parietal region of the right hemisphere of the brain. The Spatial Cognition provides the capacity to integrate the sensorial stimuli in an adequate way to form spatial perception, as well as to enable one to imagine spatially despite experience. Any disturbs of Spatial Cognition will result in deficits and alterations in Spatial Perception, as well as in Spatial Imagination. Here we should emphasize that, in opposition to Spatial Perception and Spatial Imagination, Spatial Cognition is not a consciousness phenomena. It is not an event that occurs in the minds, but the underlying capacity which makes every experience possible. It is also ‘a priori’, because this capacity must exist before the occurrence of any spatial experience.

4

Tobias Alecio Mattei

2.4. Geometric Knowledge Geometric Knowledge can be understood as the knowledge which can be obtained through informations present in both Spatial Perception and Spatial Imagination, or that which can be deduced from them. One of the most common origins of Geometric Knowledge is Spatial Perception, after measurements and manipulation of data present in sensorial inputs from sight, hearing or touch. However, some Geometric Knowledge can also derive form Spatial Imagination. This fact can usually be demonstrated when someone judges the validity about the statement of the Euclidian Geometry (for example, when evaluating the statement: ‘There are no point of intersection between two parallel straight lines’ or ‘There is only one straight line which passes simultaneously by two given different points’.) Table 1. Table demonstrating the characteristics of defined theoretical terms.

Spatial Perception Spatial Imagination Spatial Cognition Geometric Knowledge

COMPONENTS A priori Empiric x x x NO x NO x x or NO

OBJECT CLASS Consciousness Phenomenon Consciousness Phenomenon Mind Ability Group of Axioms and Theorems

Geometric Knowledge is, therefore, the objective information which can be obtained from both Spatial Perception and Spatial Imagination. However, while these last two are consciousness’ phenomenon of a specific individual, the Geometric Knowledge is the relation between those concepts and laws, such as axioms, theorems and rules. This knowledge is, therefore, informations that, although obtained through psychic phenomenon (perception and imagination) is not, in itself, a phenomenon of consciousness, and do not have, therefore, the temporal and personal character imposed by it.

3. EMPIRIC KNOWLEDGE X “A PRIORI” KNOWLEDGE Empiric knowledge is the one which can be derived from experience. It is said to be “a posteriori”, in opposition to the ‘a priori’ which exists before any experience. For empirical knowledge, only sensorial observations can offer the kind of argument that a person needs to be in a condition to say that a certain judgment is true. For Kant, strict universality and necessity are safe signs, each one infallible, that a certain knowledge is “a priori”, not empiric. Sciences such as Physics, Biology and History – especially dedicated with matters related to empiric knowledge – must be settled in observations. In opposition, subjects such as Logic, try to obtain “a priori” knowledge of the rules that govern the validity of arguments, not necessitating, therefore, any empirical observation in order reach its conclusions. Therefore,, the question we face is: What about the Geometric Knowledge? Is it similar to Physics and Biology (empiric) or to Logic (“a priori”)?

The Antique and the Modern

5

4. ANALYTICAL KNOWLEDGE X SYNTHETIC KNOWLEDGE According to Kant, to ‘know something’ or to ‘believe in something’, means to elaborate a judgment. Kant described a mental act of formulating a judgment as a task of connection of concepts, which are united in consciousness [2]. According to this view, someone who knows that all dead people are non-living joined, in his consciousness, the concept of “dead” and the concept of “non-living’ (this person used what logic names the universal affirmative connector). In another example, someone who knows that dogs don’t fly united, in his consciousness, the concept of “dog” and the concept of “flying” (using the universal negative connector). Kant imagined that a distinction should be established between two kinds of basic judgments. In one side, there are those judgements in which the mind synthesizes or joins concepts in a way that doesn’t resemble any previous connection that both might have: these are called synthetic judgments [3]. The judgment, for example, that “no dog flies”, is a type of synthetic judgment, because there is nothing, in the concept of “dog” that intrinsically excludes the act of flying. On the other hand, there are judgments in which the mind after analyzing a concept, and by a simple application of logical rules, develops a conclusion. These are called analytical judgments. The judgment that “all dead are non-living” is an example of an analytical judgment, since the concept of “non-living” is an intrinsic part of the concept of “dead”. According to Kant’s ideas, we can affirm therefore that: one judgment is analytical if, and only if, nothing more than reflection about the concepts contained in the premises is necessary in order to reach the postulated consequences [4]. A judgment is synthetic if, and only if, the reflection about the concepts contained in the premises is still not enough to determinat the truth about the judgment. According to Kant, the paradigmatic examples of analytical truths would be the logical statements, which are true simply by their logical form, despite their content. Kant sustained that every statement which dependeds only on its logical form to be truth is analytical. All the other statemnts could be considered synthetical [5]. In order to justify synthetic judgments, it is necessary, according to Kant, to a tertium quid (a third thing) that would justify the consequences based on the premises and, therefore, would make a judgment true. In relation to the synthetic judgments of empiric character, this “third element” capable of justifying, would be the sensorial experience. A person may have seen several elements that fit in the concept of dog, and none of them was able to fly. Through induction, and based on a relatively large number of empirical observations, this person states the synthetic judgment that “no dog flies”. This judgment can, of course, loose its validity if, for example, one day this person find a dog that flies; this fact would nulify the corroboration given by all the other experiences which justified the judgment. Following these lines of reasoning, we could easily perceive a simple rule: that analytic judgments are ‘a priori’ – and do not depend on experience - while synthetic judgements are empiric and depend on the experience. What about about synthetic and “a priori” judgements? Suppose we have an “a priori” knowledge (that is, before any sensorial experience) and synthetic (that is, not justifiable by the intrinsic connection of the concepts in themselves– in other words, a judgment where consequences are not justified by the logical form of the premises). Kant named these type of judgements “Transcendental Conditions of Objectivity”.

6

Tobias Alecio Mattei

They are “a priori” but synthetic knowledge. They are a priori because they are before any experience, but are synthetic because they cannot be derived from simple logical deductions based on the premisses. According to Kant this type of knowledge ius contained in every experience, but had already been established before them. Such special conditions were, according to Kant, in number of 11 (the so-called 9 ‘categories’ plus time and space). An easy way to understand what these ‘a priori’ and synthetic knowledge are is to look at the process of representing the world as knowledge. In this schema, we first have the subject of knowledge in face of the real world or “thing itself (Ding an sich)” or like Kant named: “numenum”. Between the world and the subject, there are the ‘Transcendental Conditions of Objectivity’, similar to “glasses” through which the subject sees the reality. In this heuristic process, the world is perceived and represented in human mind, after taking the imposed by these Transcendental Conditions.

5. DEMONSTRATIONS 5.1. The Geometric Knowledge Is Synthetic To Kant, it seemed evident that the fundamental geometric laws were not simple verbal truths and, therefore, that it was not possible to make them equivalent to logical truths. Therefore, Kant sustained that the fundamental laws of Geometry as well as the definitions of its primitive terms had an essential synthetic character [6]. Considering the geometric statement: that the sum of the angles of a triangle is equal to two right angles. This statement is synthetic since it is not true only because of its logical form. Nothing in the linguistic logics supports the affirmation that the sum of the angles of a triangle needs needs to be 180º. This is truth, but only because we are considering it in the context of the Euclidian Geometry. Nevertheless, there is nothing in logics that makes us consider this Geometry as the only true one. It is only because the Euclidian Geometry is the one which best fits our perception, that we believe such necessity to be true. In other words, it is not Logics that demands that the sum of the angles of a triangle should be 180º but the Euclidian Geometry. When studying the Riemann’s Geometry, for example, the sum of the angles of the triangle is always more than 180º. S. Baker presents the following definition which helps to evaluate if an statement is analytical in its character [7]: “A statement could be qualified as an analytical statement if nothing more than the comprehension of the affirmation is necessary to know that it is true. To notice that it happens this way, consider the imaginary case of someone who, examining a statement, doubts of its authenticity. How to describe the intellectual situation of this person? If a person doubts of such a statement, the doubt should itself, be enough to reveal that such person didn’t comprehend the statement”. In opposition to analytical statements, in synthetic judgments, someone is allowed to doubt about the statement, even having comprehended it. When someone says that “no dog flies”, it is perfectly possible at the same time to saythat such person comprehend the statement but doubted about its truth, for example by imagining the existence of some unknown dog which might possibly fly. In such case, it is perfectly

The Antique and the Modern

7

reasonable to state that such person fully comprehended the statement but still doubted of its truth. According to such definition, would the Geometric Knowledge be analytical or synthetic? In other words, is geometry valid only because of its terms or is it possible to have reasonably doubt about its statements? It is clear for everyone who studied analytical geometry that in order to judge a statement like: there is no unique plane that contains two perpendicular straight lines, it is necessary to “think” about it, or to represent the situation in our imagination. The simple analytical reflection about lines and planes is not sufficient to make our statement true or false. It is necessary to appeal to the spatial cognition (to an inner reality of the space represented in the human minds) which, as seen it before, can ressemble the representation of space outside us (in the case of spatial perception), or simply be the product of an imaginary mental activity (in the case of spatial imagination). We could, therefore, say that geometric knowledge is synthetic because: 1) Its statements are not valid by themselves with basis on its logical form. 2) There must be an inner experience in the human mind in order to support the validity of such statements.

5.2. The Geometric Knowledge has an “a Priori” Component The concept of “a priori”, according to the nineteenth-century psychologist Jean Piaget, includes three basic aspects: the idea of necessity, the idea of previous logical condition and the idea of previous genetic condition. It is in reference to this last aspect to the concept of “a priori” that we refer to when we say that Geometric Knowledge is “a priori”. We mean that Geometric Knowledge depends on Spatial Cognition, biologically and genetically determined. About the possibility of geometry be considered an “a priori” knowledge, S. Baker affirms [8]: “The axioms and theorems of Geometry do not need to be empiric statements; they can be announced “a priori”. Geometries postulates can only come to be true or false when they receive a specific interpretation.” This ‘a priori’ component of Geometric Knowledge inserted on the sensorial informations by the human brain whenever the Spatial Perception is generated. It can be understood as a specific tendency of the human mind, determined by a certain pattern of the neuronal circuits of the human brain, to integrate the spatial information obtained from the senses in such singular way. It corresponds in Kant philosophy to a Transcendental Condition of Objectivity (the ‘glasses’ through which reality is seen). Such pattern is similar to all human beings and is determined by a certain pattern of neuronal circuitry of the human brain. Because it is independent and before any form of sensorial experience it is said to be “a priori”. According to Piaget [9]: “Perceptions are assimilated, since the beginning by cognitive mechanisms of a superior level to them, which makes them inclined to certain particular interpretations. The Perception

8

Tobias Alecio Mattei never offers by itself direct information as if it was a copy of the object, as logical positivists defended. Every Perception contains perceptive schemas as well as an unconscious preinferences.”

The perception would be, therefore, a process in which the subject fits the object as well as enriches it while it is perceived. This position stands against the pure empiric philosophy, which affirmed that the object is already pre-established in all of its characteristics and that human beings do nothing more than assess their pre-existent qualities. This conception, however, despises the subject of knowledge and presents itself as an inadequate and simplistic description of the epistemological process. In fact pure sensations cannot give human beings the notion of space. This notion is built by the the human mind during integration of sensations, and this integrative operator is the neuronal circuitry of the posterior parietal lobe, the specific neuroanatomical area responsible for the Spatial Cognition. The sensations by themselves do not possess any spatial characteristic. Without the action of the human brain, the search for spatial perceptions and the measurements of different positions of objects in the space would be like trying to find the objective difference between a visual sensation and a olfactory sensation [10]. Such sensations differ one from another not only quantitatively, but in quality, and, therefore cannot be compared or measured. Nevertheless, after the formatting of such inputs by the human brain in a “spatial way” by such an “a priori” innate element, such as statements about Spatiality and Geometry are possible. The “a priori” component of the Geometric Knowledge becomes more explicit when one considers its origin from Spatial Imagination. As previously discussed, it is possible for a person to think spatially without the empiric information provided by an external object present at one specific moment (perception), or in the past (memory). In the case of spatial imagination, therefore, the origin of the Geometric Knowledge which is obtained is essentially “a priori”; in other words, resides entirely on the innate capacity to think in ‘spatial terms’.

6. CONCLUSIONS After this exposition we could therefore conclude that: The Spatial Cognition is the innate capacity of the human mind that permits the individuals to “think spatially” and provides the “a priori” component to the Geometric Knowledge. The posterior parietal cortex is the neuroanatomical area responsible for such Spatial Cognition, representing the anatomical substrate of what has been called by Kant as the Transcendental Condition of Objectivity of Space. The Spatial Perception is said to have two components: one “a priori”, derived from Spatial Cognition and one empiric, derived from the sensorial information’s. Spatial Imagination, nevertheless is said to possess only the “a priori” component. Therefore the Geometric Knowledge, when originated from Spatial

The Antique and the Modern

9

Perception, will also have two components: one empiric and one “a priori, when originating from Spatial Imagination, would have only the “a priori” component. The Geometric Knowledge is synthetic because its characteristics do not depend on logical deductive rules but on the biological structure which mediates it.

APPENDIX - THE RIGHT POSTERIOR PARIETAL CORTEX The right posterior parietal cortex is a complex heteromodal association area related to processing of geometrical and spatial informations. It receives input from many other brain areas and integrates them in order to provide a whole representation of the spatial aspects of the objects of the world. [10]

Figure 1. Schema of cortical brain areas related to Spatial Cognition. Note that the right posterior parietal cortex is a multimodal association areas which receives input from several other cortical areas.

Inputs from visual, tactile, proprioceptive and auditory areas are all integrated on the right posterior parietal cortex, providing to the subject the capacity of constructing an internal map of the world [11]. Such internal map can be combined with intentional plans generated in cognitive areas of frontal lobe and sent to the premotor area which by itself would be responsible for structuring the limb movements necessary to perform the appropriate movements [12]. The posterior parietal cortex should not be understood as a dedicated center containing a spatial map but as a critical gateway to access and integrate informations related to the representation and exploration of the external space [13]. When this area is injured some modality-specific channels of information (for example, the visual and auditory) related to extrapersonal space may remain intact, but they cannot be combined in order to create an interactive and coherent representation necessary to the adaptive development of spatial attention. Several complex neuropsychological deficits have

10

Tobias Alecio Mattei

already been described as associated with such ‘parietal syndrome’ [14]. Patients with lesions in such are, have been described as failing in tests involving “mental rotation” , and not being capable of identifying objects seen from an uncommon perspective; Other patients with similar deficits in the same area might have extreme difficult to find paths as well as to navigate their own bodies in relation to external solid objects like chairs and beds [15,16].

REFERENCES [1] [2]

[3]

[4]

[5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15]

[16]

Jaeger, W. A. Fundamentals of the History of His Development Oxford: Oxford University Press, 1948. Kant, I. Immanuel Kant: Critique of Pure Reason. The Cambridge Edition of the Works of Immanuel Kant, edited by Paul Guyer and Allen W. Wood. Cambridge: Cambridge University Press, 1998. Kant, I. Immanuel Kant: Theoretical Philosophy, 1755-1770. Translated and edited by David Walford and Ralf Meerbote. The Cambridge Edition of the Works of Immanuel Kant, edited by Paul Guyer and Allen W. Wood. Cambridge: Cambridge University Press, 1992. Buroker, J. V. Space and Incongruence: The Origin of Kant’s Idealism. Synthese 4 Historical Library, volume 21. Dordrecht, The Netherlands: D. Reidel Publishing Company, 1981. Melnick, A. Space, Time, and Thought in Kant. Synthese Library, volume 204. Dordrecht, The Netherlands: Kluwer Academic Publishers, 1989. Poincare, H. Dernière pensées. Paris: Flammarion Publishing Company; 1913. Barker, S. F. Filosofia da Matemática. Rio de Janeiro: Zahar Editora, 1976. Piaget, J. Lógica e Conhecimento Científico: Os Métodos da Epistemologia. Porto: Editor Livraria Civilização, 1980. Popper, K. and Eccles, J. C. O Eu e seu Cérebro. Brasília: Editor UnB, 1992. Mesulam, M. Principles of Behavioral and Cognitive Neurology. 2nd edition. Oxford: Oxford University Press; 2000; 17: 22-28. Marshall, JC, Fink GR, Spatial cognition: where we were and where we are. Neuroimage, 2001; 14: 52-57. Alivisatos B, Petrides M. Functional activation of the human brain during mental rotation. Neurophychologia, 1997; 35: 111-118. 13 Kim MS, Robertson LC. Implicit representations of space after bilateral parietal lobe damage. J. Cogn. Neurosci., 2001; 13: 1080-1087. Graziano MSA. Awareness of Space. Nature, 2001; 411: 903-904. Andersen RA, Snyder LH, Bradley DC, Xing J. Multimodal Representation of Space in the Posterior Parietal Cortex and its use in Planning Movements. Annual Review of Neuroscience, 1997; 20: 303-330. Paterson A, Zangwill OL. Disorders of visual space perception associated with lesions of the right cerebral hemisphere. Brain, 1944; 67: 331-358.