I. The Concept of Mind

Contrary to a long philosophical tradition, it is very important to emphasize that the mind is not a "substance" or res . If the mind were a substance its study would be beyond the empiricist domain of science and would belong to the extraempiricist domain of metaphysics. On other hand, if the mind were a substance it would be something individual.

Nevertheless the mind is a collection of various classes of processes that can be studied empirically. These processes are just the so-called "mental processes", in such a way that we can suggest the apparently vicious circle statement: mind is the collection of the different mental processes.

In order to avoid the circularity of this statement we have to describe the various classes of mental processes. Using concepts taken from the information theory we can distinguish, in the beginning, four main types of mental processes: 1) perceptions, i. e. organized reception of information, 2) memories or storage of information, 3) beliefs, that is, judgements about the received information, and 4) plans, namely, arrangements of information to act.

But it is possible to give a more complete description of mental processes. We have sensations, from our own body (internal sensations, such as pain) and from other bodies (external sensations). We have perceptions, and in this case we manage to construct a more or less definite object. We retain memories that come from several sources. We elaborate images with diverse degrees of creativity. We form beliefs about us and about other persons, things or ideas. Also we develop inferences that permit us to obtain new knowledge from received data. We make plans to solve problems or to fulfill purposes. And obviously we have feelings and emotions.

To limit the field of mental processes we must do it empirically, and in particular we must follow the criteria of folk psychology. I claim two theses. Firstly the paradigm of mind is the human mind, and this thesis is important because the human mind is not the only kind of mind. Secondly, folk psychology, even though is not a complete theory, consists of sufficient concepts and platitudes to guide the description of the field of mental processes.

Our commonsense or folk psychology tells us that sensations, feelings, memories or beliefs are mental processes, but digestion, breathing or the movement of clouds are not mental processes. The basic reason or criterion is the relationship between the allegued mental process and the cognition of ourselves or the cognition of other living beings or things. Therefore we may say that the mind is a collection of classes of cognitions.

I have said that the human mind is not the only kind of mind. According to the cartesian tradition, the mind is a substance (res cogitans ) and an exclusive privilege of human beings. Descartes established a clear (although wrong) criterion of mentality: something has a mind if and only if has a language. Consequently animals have not mind because they have not language. This point of view is oldfashioned and nowadays most of the psychologists admit the existence of animal mind, at least in certain degree. On other hand, the development of computer science has produced machines and robots that possess sensations, memories and also plans and inferences, whereby we can speak of mechanical mind, an idea very far from cartesian doctrines.

In consequence there are three kinds of mind: human, animal and mechanical. But I would like to insist that the human mind is the paradigm or model of mind. The attribution of mind to frogs, bees or eels is accomplished by analogy with the human mental processes; for instance, if we observe in an animal a behaviour showing reception of information, then we can attribute some type of sensation or even some type of perception to it. Likewise the attribution of mind to computers or robots is made by analogy with the human mental processes; for example, if we observe in a robot a behaviour indicating a plan of activity, then we can attribute to it some type of planning.

The existence of mechanical minds is a serious challenge to the materialism or the mind-brain identity theory. Based on this existence of mechanical minds, we can put forward what I have called the antimaterialist argument of machines , in my book La nueva filosofía de la mente ( Barcelona: Gedisa, 1995). The argument is the following. There is empirical evidence to show that certain machines have mental processes; the computer science and its technology have made machines that exhibit processes which in human beings we consider as sensations, memories, plans or inferences. Nevertheless there are not neurological processes in theses machines, because they are not built of neurones or nerve-cells. Therefore the identity between mental processes and neurological processes is refuted, since there are mental processes alien to neurological processes.

It is very interesting to realize that the development of machines, encouraged by the mechanistic materialism, turns against the materialism as an attempt to reduce the mind to the physico-chemical mechanisms of the central nervous system.

II. The Concept of Intelligence

As the mind is a collection of various classes of processes, the intelligence is a class of processes. So instead of saying that a person, an animal or a machine has intelligence is more correct to say that this person, that animal or that machine has intelligent processes.

But first of all we have to emphasize that intelligent processes are one class of the mental processes, in such a way that the mind is the genus and the intelligence is a species of this genus. In other words, all intelligent processes are mental processes, but not all mental processes are intelligent processes. For instance, an animal can possess sensations and memories but be deprived of proper intelligent processes.

It is very common among psychologists to defend that the intelligence is not an abstract faculty. On one side the intelligence is not an individual thing, but a class of processes, as I have already remarked. On the other side, intelligent processes are relative to different contexts, in such a way that we can say that a general intelligence does not exist. Intelligent processes should be understood by specifying a domain of application. For example, we can not compare the intelligence of a computer to prove theorems and the intelligence of a beaver to construct a lodge.

However the main question about intelligence is its definition. Psychologists have offered several characterizations, such as ability to learning, problem solving capacity, or power of reasoning. Nevertheless it is advisable to try to find a broad definition that can be shared by computer scientists and psychologists. In this case the best candidate for an adequate definition is problem solving capacity.

A problem for a subject is a difficulty appeared to it, in its practical (everyday) activity or in its intellectual activity, whose solution is not provided by mechanical and inborn resources, and in particular the solution is not obvious because it is lacking or there are several possible solutions.

The capacity to solve problems is a clear and definite criterion of intelligence. An intelligent process is a kind of mental process that brings about the solution of a problem. Surely, all types of reasoning are intelligent processes, and specifically (in the intellectual activity) all sorts of explanation are intelligent processes, namely deductions, abductions and inductions.

Again, like in the mind, the human intelligence is the paradigm or model of the intelligence. The attribution of intelligent processes to rats, cats, dogs or dolphins is made by analogy with the human intelligence. By the way, behaviourism, currently discredited, played an important role in the study of animal intelligence.

On other hand, the attribution of intelligent processes to some computers and some robots is also accomplished by analogy with the human intelligent processes. For instance, we attribute intelligence to the Logic Theorist ( created by Newell, Shaw and Simon) because this computer programme is able to prove logical theorems like a logician.

The attribution of intelligence to animals is easily accepted by psychologists and it is frequent among philosophers of mind. But the attribution of intelligence to some computers and some robots has started a vivid and long debate. Obviously I will not deal with this debate, but I will declare my position.

The distinction, drawn by John R. Searle, between strong artificial intelligence and weak artificial intelligence is already usual. According to weak artificial intelligence, the computer is a very powerful tool for the simulation of the mind, but it is a wrong doctrine to defend that computers have mind ( hence it is a wrong position to claim that computers have intelligence). According to strong artificial intelligence, the computer is not merely a tool in the study of the mind, rather the appropriately programmed computer really has a mind (hence the computer can have intelligence).

I think that there are three kinds of intelligence: human intelligence, animal intelligence and mechanical intelligence. The pervasive and repeated Searle´s chinese room argument is misleading, because Searle believes that it is possible to maintain a sharp distinction between syntax and semantics. In fact, we can distinguish the form or syntax in a chain of natural language statements from its semantics or concrete meanings, but the forms or structures of language are types of arrangement of symbols by virtue of which the chains of statements have one general way or another of meaning. Therefore each form or structure of language has a general way of meaning, whereby it is not possible a sharp distinction between syntax and semantics.

III. The Concept of Spirit

From the beginning of human history the human beings have considered themselves as a dual reality using at least two arguments. On the one hand, they could discern their actual lives and their imagined lives after death. On the other hand, they could discern their bodies, among other bodies, and their wills, which could feel alien to their bodies and dissatisfied with them. This dualism between what we actually are and what we will be or we would like to be is something present in the thought of mankind from the beginning of history. The early myths and religions already bear witness to this idea of human being as a dual reality.

The mind-body problem first of all refers to this duality perceived or imagined by human beings. However we can distinguish three different formulations of the general mind-body problem: a religious version, a philosophical version and a scientific version.

The religious formulation of the mind-body problem upholds that the duality is between body and soul, i. e. between what we have in common with the material realities of this world and our soul as immaterial reality alien to this world. I call this version Augustine´s problem.

The philosophical formulation defends that the duality is between the body, which is public, observable by the others and governed by mechanical laws, and the mind, which is private and it is not governed by mechanical laws. Naturally I call this version Descartes´ problem.

Finally, the scientific formulation of the mind-body problem puts forward that the duality in the human beings is or would be between the brain, as studied by neuroscience, and mind, as studied by cognitive psychology and artificial intelligence. I call this new version Penfield´s problem.

Obviously I will not deal with all theses problems, but I will declare my position in the Penfield´s problem. In my paper "Procesos mentales y cognitivismo" ( Revista de Filosofía , vol. V, nº 7, 1992) I have defended a reasonable dualism. Briefly speaking I maintain that there are three general categories of mental processes. Firstly, there are brain-mental (hence physical) processes, that we can find in human beings and in animals (at least in vertebrates). Secondly, there are physical-mental (but non-cerebral) processes, that we can find in certain machines. Thirdly, there are non-physical-mental processes (which can be called spiritual), that we find exclusively in human beings. Therefore the notion of spirit refers to spiritual processes, which must be understood as processes produced by a non-physical causation, that uses neural means but exceeds these neural means.

We can give some outstanding examples of spiritual processes. First of all we have the phenomena of selfconsciousness. In this point it is very important to distinguish between simple consciousness and selfconsciousness. When I remember certain event in my last summer I can be conscious of this memory; in this case I have simple consciousness. But when I feel myself the same in my childhood, in my youth and now, then I am selfconscious. So while simple consciousness consists merely in paying attention to a concrete mental process, selfconsciousness consists in feeling myself the subject of all my mental processes.

Therefore simple consciousness means basically introspection of a concrete mental process, but selfconsciousness means strikingly autoreference to all the mental life. This autoreference in so far as it supplies us with the knowledge of our personal identity, all through past, present and future, is not reduced to neural processes, which are developed in a fixed time.

Another example of spiritual processes is given by free volitions. In this case it is crucial the distinction between simple or determinist volitions and free or indeterminist volitions. The field of volitions (intentions or wishes) constitutes in every human being something characteristic. We can assess the character of a person if we know his/her intentions. Unfortunately the intentions of a person usually remain a secret for us, and sometimes they are also partly unknown for him/her. Therefore volitions are a very important kind of mental process.

But we have to examine the distinction between simple volitions and free volitions. My wish of having lunch at one o´clock, after being without eating since eight in the morning, is a determinist volition. My intention of taking revenge for a grave offence is also a determinist volition. In both cases my volitions are determined by stimuli and conditions related normally with them. On other hand, my decision of going on a hunger strike, or my decision of forgiving a very serious offence, are free volitions, since they are contrary to the determination of stimuli and normal patterns of behaviour. The whole of free volitions constitutes the proper freedom. This freedom is spiritual in so far as it is not reduced to neural processes, which are mechanical and determinist.

Finally, another example of spiritual processes, typical of human beings, is the constitution of a personal project of life. Every human being is not forced to live according to the dictates of his instincts and according to the empire of the conditions of his milieu, but he can constitute a project of life to guide his personal activity. This project of life includes the choice of a meaning for his life taken as a whole. In other words, our genetic programme determines our physical constitution and our environment conditions our activity, but the choice of our project of life is an overdetermination added to our physical character.

To sum up, a human mental process is spiritual if it exhibits properties that exceed the physical determination of stimuli and patterns of behaviour or the concretion of the time.

IV. Intelligence and Freedom

From the beginning of scientific activity the human beings have defined themselves as rational or intelligent, so excluding intelligence not only from animals but also from machines. Currently most of us admit that at least some animals (like cats and dogs) have intelligence, although we consider their intelligence as inferior to ours. But currently most of the human beings do not accept the existence of intelligent machines.

However the existence of intelligent machines is an empirical fact, just like the progressive development of artificial intelligence. We have machines that prove logical and mathematical theorems, machines that diagnose illnesses, or machines that defeat chess champions. To the persons thinking that human beings are defined by rationality Sigmund Freud´s thought was a radical challenge, because he insisted on the importance and relevance of human irrational aspects. A popular Brazilian samba (Martinho da Vila´s "Verdade verdadeira") summarizes the situation very well: man is not an animal but he is irrational. This samba is masterfully opposed to the classical definition of man as rational animal. In our century, when the technological rationality has shown all its capacity of perversion, we begin to doubt whether the rationality should be considered the human superior quality.

People that feel that the existence of intelligent machines would be an humiliation for them, because human beings would lose the privilege of the rationality, are not able of appreciating other human aspects.

Usually, and from the beginning of scientific activity, the intelligence has been considered the most important quality of human beings. The rational capacity has been the criterion of evaluation for persons. The scientist has become the model human being.

But freedom, i. e. the whole of free volitions, is a more specific quality of human beings than intelligence. There are animal intelligence and mechanical intelligence, but there are not animal freedom nor mechanical freedom. A proper criterion of evaluation for persons would be their capacity of being free, using their freedom to look for the good and to avoid the evil. We should admire the good persons instead of mocking them.

However, although freedom is a specific human quality and something valuable in itself, in relation with its objects can be a good value or a wrong value. Freedom can possess excellence or possess vileness depending on its use. A crime, like a heroic action, can be a free volition. Freedom, as we have seen, belongs to the spiritual realm. But this realm, just because of freedom, is not only the realm of goodness.