Hayek's Evolutionary Epistemology, Artificial Intelligence, and the Question of Free Will

By Gary T. Dempsey

Abstract

This paper examines the evolutionary epistemology of the Austrian economist Friedrich Hayek. I argue that Hayek embraces a connectionist theory of mind that exhibits the trial-and-error strategy increasingly employed by many artificial intelligence researchers. I also maintain that Hayek recognizes that his epistemology undermines the idea of free will because it implies that the mind's operation is determined by the evolutionary interaction of the matter that comprises ourselves and the world around us. I point out, however, that Hayek responds to this implied determinism by explaining that it can have no practical impact on our day-to-day lives because, as he demonstrates, the complexity of the mind's evolution prevents us from ever knowing how we are determined to behave. Instead, we can only know our mind at the instant we experience it.
Key words: Connectionism, complex adaptive system, long-term potentiation, nonmonotonic reasoning, physiological memory, self-organizing maps, spontaneous order.

In the field of economics, Friedrich Hayek (1899-1992) has been long recognized for his contributions to the discipline, and in fact was awarded the Nobel Prize in 1974 for his pioneering work in the theory of money and economic fluctuations. But it should be noted that Hayek's original scholarly interest was in the natural sciences, not economics, and that it was in the area of theoretical psychology that he first raised the issue of self ordering in complex systems. Indeed, in the winter of 1920, one year before going to work with his eventual mentor, economist Ludwig von Mises, Hayek wrote a manuscript that asked 'how can order create itself within our neural fibers?' ¹ That manuscript would be supplemented and was eventually published in 1952 under the title The Sensory Order: An Inquiry into the Foundations of Theoretical Psychology.

Throughout The Sensory Order and later writings, Hayek makes it clear that the apparatus that allows us to know the world—the mind—is itself subject to evolution; that is, it is a 'work in progress' prone to modification by experience. The mind, he explains, is “incessantly changing” (1984, p243) and its contents constitute an adaptive “capacity to respond to [its] environment with a pattern of actions that helps [it] to persist” (1973, p18). This view puts Hayek squarely in the camp of the evolutionary epistemologists. Indeed, like Donald Campbell (1960, 1974), Karl Popper (1972, 1984, 1987), Konrad Lorenz (1977, 1982), and other expositors of the evolutionary model of human knowledge, Hayek maintains that knowledge is the product of trial-and-error learning and that our minds are characterized by gains in adaptive advantage due to the selective retention of useful representations of the physical world.

It is not surprising, then, that scholars have concluded that Hayek's epistemology has an essentially “evolutionary character” (Kukathas 1989, p49), or that Hayek takes the “evolutionist standpoint” (Gray 1986, p11) or the “evolutionary perspective” (Vanberg 1994, p96) in his epistemology. In the following essay, I attempt to piece together Hayek's epistemology and to explore the particulars of its evolutionary quality. I begin with a brief overview of Hayek's connectionist theory of mind, followed by an account of his evolutionary epistemology. This latter section consolidates Hayek's diverse thoughts on evolution to bring them into sharper focus for our discussion and shows how his view anticipates a number of conceptual developments in artificial intelligence. Finally, I explain how Hayek's epistemology undermines the idea of free will and how he responds to this claim.

The Connectionist Mind

At bottom, Hayek is a materialist. For him, there is no mind-body split. Instead, all our thoughts, memories, and ambitions result from the operation of matter. Indeed, for Hayek, “the assertion that...mental phenomena are 'nothing but' certain complexes of physical events [is] probably defensible” (1989, p88). Or more assertively, “mind is...the order prevailing in a particular part of the physical universe—that part of it which is ourselves” (1952, p178).

Hayek's materialism begins with the recognition that the locus of the mind—the human brain—is made up of a vast weave of fibrous cells called neurons; the cerebral cortex being the most dense with more than ten-thousand million. Each of these neurons, in turn, can be functionally connected to neighboring neurons via junctions called synapses; the potential number and complexity of connective patterns that can be built up between them is therefore practically unlimited. It is out of this universe of possibility, says Hayek, that the order we call 'the mind' emerges.

With respect to the formation of the mind, Hayek contends that the sensory experiences the brain processes are not unitary, but entail a collection of impulses. That is to say, like a suitcase filled with an assortment of shirts, pants, shoes, belts, socks, etc., sensory experiences are made up of many impulses corresponding to various aspects of the observed object or event. What is more, these impulses emanate not from one, but from many neighboring receptors in the sensory organ, and they occur in conjunction with still other impulses associated with participation in a specific kinesthetic activitysuch as touching, looking, or listening. This package of impulses then courses through our nervous system and, through what Hayek calls “physiological memory” (ibid., p53), forges connective pathways or “links” (ibid., p104) between neurons. Such connections are formed, says Hayek, because the electrochemical impulses triggered by sensory stimuli change the “threshold of excitation” (1978c, p40) of affected neurons so that future impulses are 'positively weighted' or flow more easily through those already in “a state of preparedness to act” (ibid.). This view is not without some basis in modern neuroscience. Neuroscientists maintain that sensory experiences, especially recurrent or traumatic experiences, generate connections between neurons. What occurs is a physiological process called long-term potentiation, or LTP (Baudry and Davis, 1996). The LTP process involves changing the efficiency of synaptic transmissions along pathways that connect neurons—in other words, certain electrochemical signals travel more easily along LTP pathways. According to this theory, the connective pathways between neurons possess a class of postsynaptic amino acid receptors known as NMDAs. NMDA receptors are activated each time the pathway is confronted with an electrochemical impulse so that the receptivity of neurons with worn NMDAs is enhanced over time.

As there are a multiplicity of impulses associated with each sensory experience we encounter, impulses from different sensory experiences may employ one or more of the same neural pathways. There will occur, in other words, an overlapping of physiological memory. This overlapping is perhaps the single most important concept of Hayek's theory of the mind for it leads to what he calls “simultaneous classification” (1952, pp180-181). Simultaneous classification is the idea that sensory experiences are at the same time related to all sorts of other sensory experiences via shared neural pathways. These shared pathways have the effect of grouping together or categorizing sensory experiences along the lines of a neural commonalty. Returning to our suitcase metaphor for sensory experiences, it would be as if one containing shirts, pants, and shoes was linked to all the others with shirts, and at the same time linked to the ones with pants and, still further, linked to all the ones with shoes. The concept of simultaneous classification, in other words, means that at any given moment a sensory experience will be a member of more than one class of events, related through physiological memory to many other sensory experiences.

Hayek also contends that there are connections that 'negatively weight' or inhibit the flow of impulses (1952, pp67-68). This not only defines a second way that the brain's electrochemical impulses are channeled, but compounds the complexity of neural patterns by introducing the possibility that different impulses can create connections that oppose or counteract each other.

Broadly speaking, this account of brain functioning conforms to what is called a connectionist model. This is a term that Barry Smith (1996) also applies to Hayek's theory of mind. What I (and Smith) mean to suggest by using this term is not only that neural connections form the focus of Hayek's model generally, but that there is an affinity between Hayek's views and those of the research field pioneered by Warren McCulloch and Walter Pitts (1943) that today encompasses artificial neural networks. As a historical matter, moreover, it should be recalled that one of the first connectionist computer models of the brain, Frank Rosenblatt's Perceptron, was directly inspired by the writings of Hayek and psychobiologist Donald O. Hebb (Rosenblatt 1958).

Under Hayek's connectionist model of brain functioning, the “possibilities of classification of...different individual impulses and groups of impulses...are practically unlimited [and] adequate for building up an extremely complex system of relations among millions of impulses” (ibid., p71). As Hayek sees it, initial sensory impulses destined for the brain “pass in a great variety of directions...merely diffus[ing] and dissipat[ing] themselves in our neural fibers” (ibid., p120). An afferent impulse arriving for the first time, in other words, will “not yet occupy a definite position in the order of such impulses,” or have a “distinct functional significance” (ibid., p103). “But since every occurrence of a combination of such impulses will contribute to the gradual formation of a network of connexions of ever-increasing density, every neuron will gradually acquire a more and more clearly defined place in the comprehensive system of such connexions” (ibid., p103). It is out of this 'thickness' of connections that we are able to detect patterns and come to know the world. In fact, says Hayek, one of the things that distinguishes an adult mind from an infant mind is that an infant has a “much thinner net of ordering relations” (1978c, p44). Thus our experience is “richer than theirs as a consequence of our mind being equipped, not with relations which are more abstract, but with a greater number of abstract relations” (1989, p66).

This intimate relationship between neural connections and sensory experiences leads Hayek to what is called the correspondence theory of perception—the idea that the physical workings of the brain come to map things out in the world. As Hayek puts it, the “mental order involves...a gradual approximation to the order which in the external world exists between the stimuli evoking the impulses which 'represent' them in the central nervous system” (1952, p107). Hayek, however, is careful to point out that our representations are not in some manner originally attached to, or an original attribute of, the individual physiological impulses or stimuli. Rather, the process of physiological memory creates the distinctions in question. Indeed, the representations are “determined by the system of connections by which the impulses can be transmitted from neuron to neuron” (ibid., p53). This may also be expressed as the specific character of a particular representation is “neither due to the attributes of the stimulus which caused it, nor to the attributes of the impulse, but [is] determined by the position in the structure of the nervous system of the fiber which carries the impulse” (ibid., p12). In other words, a given sensory impulse does not in and of itself designate specific mental representations. Rather, a mental representation is designated by the order of all the connections established in the mind.

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