Gerald Edelman
Second Nature
Brain Science and Human Knowledge
Yale University Press 2006

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I argued that the brain is not a computer and that the world is not a piece of coded tape. The brain must, in the absence of unambiguous signals, establish regularities of behaviour under constraints of inherited value systems and of idiosyncratic perceptual and memorial events. In human beings, such systems and events necessarily involve emotions and biases.

Selectionistic brains themselves show the effects of historical contingency irreversibility, and the operation of non-linear processes. They consist of enormously complex and degenerate networks that are uniquely embodied in each individual.

Moreover, human brains operate fundamentally in terms of pattern recognition rather than logic. They are highly constructive in settling on given patterns and at the same time are constantly open to error. This is seen in perceptual illusions as well as in higher-order beliefs. But as shown by the analysis of learning, error correction is usually available in response to appropriate rewards or punishments.

When we consider modes of thought pursued by selectionistic brains, there is a set of relations between pattern recognition and logic that is both contrastive and reinforcing.

A fundamental early mode of thinking that is highly dependent on pattern recognition involves metaphor. Metaphor is a reflection of the range and associativity of enormously complex and degenerate brain networks. It is pertinent that the products of metaphorical thinking can be understood but cannot be proven as can simile or logical propositions.

Language itself reflects the constructive yet inherently ambiguous and indeterminate aspect of this mode of thought.

Although all of our brain functions and cognitive capacities are constrained by physics and can be understood as products of natural selection, not all of these capabilities can be treated successfully by reduction.

Conscious experiences themselves are enormously complex discriminations in a higher-order qualia space, and each individual's history and set of brain events are unique. Although there are certainly regularities of intentionality and behaviour, they are variable, culture- and language dependent, and enormously rich. Subjectivity is is reducible.

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The sequence is clear: following the evolution of Homo sapiens, the emergence of language and higher-order consciousness allowed the development of empirical science in the service of the verifiable truth. The application of logic in relation to language and observation of the world, and of mathematics as the study of stable mental objects, profoundly enhanced these developments.

Nonetheless, these developments occurred within a specific historical matrix that cannot be reduced to them or by them. Moreover, there is no contradiction in the fact that selectionistic brains capable of higher-order consciousness and pattern recognition could create artistic, aesthetic, or ethical systems within particular historical and cultural conditions. We can conclude that there is no logicaly necessary divorce between science and humanities, only a tense relation in which science is admitted as a fundamental but not exhaustive or exclusive basis for grounding our knowledge.

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,,,analyse the causal connections of brain action

Given the selectionistic properties of the brain, no adequate reduction of human sciences to the brain's so-called epigenetic rules is realisable.

The brain operates by selectional matching of its non-linear variant repertoires with occasionally novel and non-linear events provided by world and self signals.

With the advent of true language and higher-order consciousness, enormous numbers of discriminations can be experienced. The degeneracy and associativity of these discriminations are accompanied by an even more enormous set of combinations and recombinations of states integrated by the dynamic core. These states are not necessarily veridicial and, in addition, are often constructive, contingent, and context dependent.

The mode of thought that results from these operations initially involves pattern recognition and not logic. Because selection in this neural system is constrained by the operation of heritable value systems and perceptually-based memory, the system entails intentionality, beliefs, desires, and emotional states.

Such a system is as subject to contingent events from within as it is to external contingencies. It can exhibit singular states as well as regularities, and some of these states are experienced as a private, irreducible features of subjectivity.

All of these properties are expressed in one degree or another in thinking and in language. Early on in thinking, metaphor can dominate, and even after the application of logic, language is rich with metaphorical expression. Moreover, language itself shows indeterminacy in reference and translation. The ambiguity that is inherent in natural language is not a critical weakness, however. On the contrary, it is the basis of the rich combinatorial power that we recognize in imaginative constructions. These properties are just what one would expect to result from the operation of selectional brain.

Scientific insight results when this power is constrained by logic, mathematics, and controlled observation. But not all judgement and thought can be reduced to scientific description. A key example is the area are of normative judgement seen in ethics and aesthetics.

These limitations on scientific reduction do not mean that conscious activity, language, and issues of meaning derive from some spooky realm of "
res cogitans". By explaining the neural basis of conscious thought, we can in fact reconcile the appearance of all of the rich properties of thought with physics and biology. The result is indeed a form of reconciliation, divorce is not necessary.

To provide a firm base for this reconciliation (and for a brain-based epistemology), we must address the classical question:

Are consciousness and " mental events" causal? And, if not, what is the relation between causal brain action and consciousness? The answers to these questions may startle us, inasmuch as they reveal a set of illusions that we must live with.

It is commonplace to talk of mental events or phenomenal experience as if they were causal. But inasmuch as consciousness is a process entailed by integration of neuronal activity in the reentrant dynamic core, it cannot itself be causal.

At the macroscopic level the physical world is causally closed: only transactions at the level of matter and energy can be causal. So it is the activity of the thalamocortical core that is causal, not the phenomenal experience it entails.

To make that point clear, let us define C' to be the integrated pattern of neural activity that makes up the dynamic core at a particular time. C' in tales conscious state we call C and which involves a particular set of discriminations. C' not only entails C but contributes causally to a subsequent C' states as well as bodily actions. The relationship between C' and C is faithful and for this reason, in most cases, we can speak of C as if it is causal. Indeed, C states are informative of C' states. They are our only access to such states, in as much as our neurophysiological methods cannot, at present, record the myriad neural contributions that are integrated in a given causal core state.

So we must conclude that our belief that consciousness causes things to happen is one of a number of useful illusions. The usefulness of this particular illusion may be appreciated by considering that we speak to each other in C language. But the underlying neural activity is what drives individual and mental responses.

Philosophers have found this set of conclusions to be an expression of epiphenomenalism - that consciousness does nothing. In fact, it serves to inform us of brain states and is thus central to our understanding. The traditional horror with which epiphenomenalism is met by philosophers can be abated once the faithful entailment mechanisms of reentrant core states are understood.

I have called another conscious illusion the Heraclitean illusion because it reflects our way of thinking about time and change.

Most people since the passage of time as the movement of a point or a scene from the past to the present to the future. But in a strict physical sense, only the present exists. The integration of core states leading to conscious states takes a finite time of two hundred to five hundred milliseconds. This time period is the lower limit of the remembered present. The past and future are, in contrast, concepts available only to higher-order consciousness. Nonetheless, we often think of the flow of time as we do, in terms of the movement of a Heraclitean river. Within this illusion falls the changing sense of duration we all experience under different conditions. Experienced time, unlike clock time, can seem slow fast depending on various conscious states.

These issues may be connected to two others: the usefulness of conscious discrimination in planning, over times of seconds to minutes, and a temporal relation between the activity of the core and of brain areas concerned with action and agency. As I have said, conscious states involve integration times of hundreds of milliseconds. But unconscious neural activity leading to action can lead to much faster responses. Many such responses (aside from innate startle responses) require conscious training. After deliberate practice, habitual responses are then mediated non-consciously and rapidly by sub cortical structures interacting with the cortex. Clearly, it is the play between core states, attention, and cortical responses that provides the basis for complex suits of action and movement.

Connected to the illusion of a causal consciousness and the Heraclitean illusion is the time-honoured and much debated issue of free will.

In the strict recognition that all physical events have causes, one must conclude that core states as physical events determined. Nonetheless, when not physically bound or in prison or in the throes of neural disaster we can honestly claim the ability to do "as we like" or "see fit", illusary or not. It is on this base that we hold persons responsible for acts determined by society's "oughts", and we train our children accordingly in terms of reward and punishment.

These matters are connected to the relation between normative concerns and neural states. We have dismissed the idea that "ought" comes from "is" and have repudiated the naturalistic fallacy. Nevertheless, we have all inherited a set of neural structures, value systems, that are critical to the function of our brains as selectionistic systems. The function of these systems is to provide species specific constraints on the manifold of selective events that can occur in an individual. Suckling reflexes, startle responses, and the action hormonal pathways and of autonomic neural systems affecting our metabolic and physiological states and emotions are essential to our adaptive functioning.

However, they must not be confused with the categories that arise after experiential selection under their constraint. Indeed, in humans of higher-order consciousness, the learning of categories can actually modify the setpoints of value systems. Humans, unlike most animals, have modifiable value. What ensues is not predictable: there are no animal equivalents of saints, who, even under torture can prefer death to renunciation.

So value systems may jumpstart the building of oughts in a society but do not directly determine them. Value systems also provide a brain basis for complex emotional responses... I consider that emotions are complex states arising from core interactions with value systems. The C' states that ensue are accompanied not only by feeling and cognitive content but also by the bodily responses that these states cause. The pleasure and displeasure that can arise clearly reflect the activity of modulatory value responses. But just as C' states reflect huge complexity, their interaction with value systems can also lead to enormous complexes of primary and secondary emotions, with or without cognitive concomitants. All such responses are intimately coupled to the cognitive and emotional construction of the process we call the self. In this respect, whatever errors are laid at Freud's doorstep, he must be credited for his exploration of that process and his attempts to understand it.

When we contrast the picture of generativity provided by brain-based epistemology with that of its philosophical precursors, we cannot help but be struck by a startling difference. What we have called traditional epistemology is concerned with justified true belief and persuit of truth and truth conditions. By no means should the importance of such concerns be underestimated. But their persuit is, in the end, a narrow and terminal enterprise largely preoccupied with language, meaning, and logic. It has not been the proper concerns of that enterprise to take up motivation (conscious or not) or emotion or pattern recognition per se. Nonetheless, these are all critical to our knowledge is acquired.

Although the biologically-based enterprise is considerably less elegant, it can be looked on as prior to and generative of the traditional view. A possible criticism of his conclusion is that it confounds psychology and epistemology. So be it.

It is as important to human knowledge to know how knowledge originates in the long course of evolution as it is to understand truth by disquotation. If we concur that the statement "snow is white" is true if and only if snow is white is an elegant way of assuring a certain kind of truth, it is equally important to recognize its biological as well as it social origins.

The reasons are compelling: there are various grounds for claiming truth, and these grounds must be placed in relation to their origins. To be restricted to invariance under lexical substitution (a property first-order predicate logic) is too narrow a fate. Indeed, the development of logic itself must have depended on the cultural consequences of higher-order consciousness. Creative conscious imagination complemented by logic has gone a long way in the development of scientific truth. It is therefore illuminating to ask how creativity in thought and action emerges from the operation of the brain as a selectional system.

Edelman



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