A Few Introductory Remarks

Before examining Evandro Agazzi’s theses about artificial intelligence, it is useful to dwell upon the idea of reproducing in any possible way the mental activities of humans and, more particularly, the so called rational or cognitive activities.

The idea of imitating, simulating or emulating human cognitive activities is very old, and can be dated back to the medieval logicians, and particularly to the logic of Ramon Lull and afterwards to the combinatorial logic of Pierre de la Ramee. The works of these authors were based on Aristotle’s logic, which basi­cally claimed that human thought (the strictly cognitive thought, at least) develops by logical procedures, like deduction and induction, which could always be refor­mulated in a rigorous and even formal way. Certainly Aristotelian logic did not include the idea of a reproduction of human cognitive activities, but it contained the idea that such activities are formal procedures, which could have been adapted to any type of cognitive content; in general, this idea was adopted by those who first, in the modern age, formulated the concept of reproducibility of the cognitive activities of man: they considered these activities as the result of formal processes.

Such a conception was also adopted by Ramon Lull, who was certainly the first in the history of philosophy and of logic to pass from considering the cognitive activities as logical-formal activities to believing in the possibility to imitate such activities by mean of techniques or more or less mechanical devices. Lull’s logical machines, in fact, were a kind of primitive computers formed by various disks of papers laid one on top of the other, capable to rotate and so to generate different combinations of the symbols which were printed on them. Such logical machines allowed to formulate different types of syllogisms concerning any kind of sym­bolically representable content.

He used these logical syllogistic machines to demonstrate the existence of God, and more particularly the existence and the primacy of the Christian God; his logical machines are the first, even if primitive, material form of the idea of imitating some activities of the human mind; they attracted much interest, and were resumed by other logicians in the following centuries. Such machines were able to formulate mechanically the syllogisms, and their application to theology might have been acceptable within Christian theology as a means to offer a logical proof of the existence of God; unfortunately, however, it proved unacceptable to Muslim theologians, who after a short period of interest decided that it was probably better to abandon these logical machines, and Ramon Lull was stoned to death.

But the idea of the mechanization of the human mind, and more particularly of its logic, was not abandoned, and it survived in various stages till modern logic, the formulation of axiomatic systems, and the construction of intelligent machines. This course, up to the era of the first computers like the Eniac, manufac­tured among others by Arthur Burks, had many stages, and it is useful to remind some of them. The first was the combinatorial logic of Pierre de la Ramee, and afterwards Leibniz’s logical studies and the famous machine devised by Pascal to perform mechanically some elementary arithmetical operations. If mathematical thought was typical for mankind, and if it was mechanically reproducible, then at least some part of human thought was also reproducible by a machine: in other words, a machine could be able to perform some human mental operations.

This concept of the reproducibility of human thought was further used in devising logical or mathematical machines like those of Babbage; since then the possibility of reproducing human thought has made progresses, up to the manu­facture of machines capable to perform not only mathematical operations, but also logical operations, in particular deductive operations similar to those of humans: the underlying idea has always been that of considering the mental processes as rational and logical processes grounded on rules and applicable to different contents.

Nevertheless, we must remember that, together with formal logic, in the Middle Age also other kinds of logics were formulated, where the contents of the proposi­tions involved in logical processes were also relevant: just think, for instance, of Boethius’ logical conceptions.

Within the formal view the first researchers on Artificial Intelligence (AI) held that it was possible to reproduce, or at least to simulate or emulate, human thought by a machine. Hence, their purpose was not to understand, by the use of machines, the functioning of the human brain, but to use machines to perform the same oper­ations (even if not all) that the human mind is capable to perform. So, they drove to the man-automaton equivalence.

Once again, this conception was based on the idea that human thought was the result of elementary computations which were capable to generate very complex processes. This conception was little by little abandoned within AI, in favor of a more limited objective, the construction of machines capable to realize computa­tions useful to perform specific tasks: therefore, little by little the term ‘intelligent’ was abandoned, and attention was devoted to the construction of expert systems useful to perform different tasks, like: visual recognition of objects; auditory rec­ognition of sounds; recognition of texts; management and control of very com­plicated processes, like those of airplanes, of space ships, or space probes; the performance of activities like those of robots, drones, or similar apparatuses.

However, it is useful to remind that computationalism, which took the compu­tations performed by machines as a model of the human mind, brought to a reduc­tionist philosophy of mind; in its strongest form this conception was abandoned as a consequence of results obtained in the neurosciences, according to which the human mind is much more complex than mere computational processes based on few rules applied to basic elements. This point, as we shall see, was stressed by Agazzi since the sixties of the last century.

The first theorists of AI reasoned from the premise that the mind operates always and only on the basis of logical or formal rules; hence, for them simulat­ing the human mind meant building technological apparatuses capable to perform some of its operations, and this entailed that “machines can think”. Agazzi dwells upon this statement clearly distinguishing two aspects of the problem.

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