1. Description of the obstacle

Philosophism is not the first, not the strongest, but is certainly the most persistent obstacle to the advancement of psychology. Like the villain in animated cartoons, philosophical systems keep coming back repeatedly after each defeat to threaten the science of psychology. Basically, philosophical systems are obstacles to psychology because they try to force extraneous principles (often derived from natural experience) into psychology. As Ernest Nagel noticed very well, even though new forms of philosophical psychology may address interesting philosophical issues, they rarely show any understanding of scientific psychology (Nagel 1965). This does not mean that philosophical ideas should not or do not influence science. The influence of logical positivism on psychology in the 1930's and 1940's (Deese 1972) is an unequivocal example that philosophy can affect science. But cultural philosophies and philosophy of science should not be confounded with systems of philosophical psychology. Philosophical psychology is an explicit attempt at producing psychological knowledge by philosophical means. More specifically, systems of philosophical psychology try to introduce speculative methods into the science of psychology. To a certain extent, we may say that the real obstacle is anti-empiricism rather than philosophism in general.

The expression anti-empiricism implies that speculation is not empirical (which is quite evident) and that scientific research is empirical (which is questionable in certain cases). To avoid problems, I will maintain the Bachelardian attitude of allowing science to define its own empiricism. I would be unable to argue that any science is empiricist in the sense of being guided by uncontaminated sensations evoked by autonomous objects. Some sciences, such as mathematics, can only be empirical in the sense that abstract sciences are abstract because they abstract characteristics from relations in the empirical world (Piaget 1970). Other sciences, such as chemistry and biology, have some objects that can be directly touched (such as a beaker with reagents or the gastrocnemius muscle in a frog's leg) whereas others escape strict empiricism (such as a proton in the nucleus of an atom or a third messenger in the nucleus of a neuron). Indeed, the empiricist view (including its metaphysical assumption of an a priori material world) has been questioned by a large number of philosophers since the 18th century (e.g., Kant 1924, Husserl 1964, Bachelard 1934). However, although an analysis of how empiricism is defined in contemporary sciences is well beyond the scope of this book, it would be foolish not to acknowledge the fact that science is an empirical enterprise. As Galileo used to say, nature is an open book from which science extracts knowledge (Galilei 1933). The task of science is to describe and explain the empirical world. Such a conception is evident in this statement endorsed by the National Academy of Sciences:

Many of the contemporary forms of philosophical psychology derive from the phenomenological philosophy of Edmund Husserl. One of Husserl's main goal in the late 19th century was to find an objective method of investigation in philosophy (Husserl 1965). While pursuing this goal, Husserl stumbled on the fact that psychologists were studying consciousness (which was traditionally the object of study of philosophy) using methods that he as a philosopher had never thought about. He reasoned that there should be two ways of studying consciousness, or more exactly, that there should be two types of consciousness: the empirical consciousness studied by empirical psychology and the transcendental consciousness that could be studied by his phenomenological method (Husserl 1977). This distinction in itself does not affect scientific psychology. But it is easy to see that other authors might use the distinction to claim that scientific psychology has a lot to learn from phenomenological psychology. The possibility for obstructions was, therefore, established. It is not surprising that, in a symposium about behaviorism and phenomenology, philosophers and clinical psychologists argued that the two movements could be integrated, whereas the experimental psychologists argued that no integration would be possible (Day 1969).

2. Examples of the obstacle

Anti-empiricism is an obstacle irrespective of its association with phenomenology. For example, Paul Wachtel proposed the creation of a "theoretical psychology" that would not involve experiments but would nevertheless remain scientific. One of the tasks to be performed by the theoretical psychologist would be to evaluate how dependent psychological facts are on psychological theory (Wachtel 1980). Now, although this might be an appropriate task for the philosopher of science, it is definitely not appropriate for the psychologist as a scientist. In science, the legitimacy of a fact should be decided by empirical research, not by mental fantasy. To question scientific procedures in abstract is to place philosophy above science. And the intrusion of philosophy into science is an epistemological obstacle.

Carl Rogers suggested that there are three modes of knowledge in science: subjective, objective, and interpersonal. According to him, every mature psychological science makes use of these three modes in varying proportions, and a satisfactory science of behavior can emerge only if an appropriate balance between the three modes is obtained (Rogers 1964). Now, which school of psychology has attained an appropriate balance between the three modes and, therefore, constitutes a true science of behavior? Rogers' answer: humanist psychology. Consequently, scientific psychology (i.e., behaviorism, psychophysics, biopsychology, etc.) is not really scientific and should clear the way for humanist psychology. The obstructive nature of this position requires no comment.

Another attack on psychology was made by Michael Scriven. According to him, psychology is in very bad shape, and this is due not to the fact that it is a young science but to the fact that, by its own nature, psychology is unable to go anywhere (Scriven 1964). Psychology allegedly has three natural limitations, two of which are worth mentioning: 1) psychology's field of observation has been studied by common sense for 50,000 years, which leaves very little to be discovered now; and 2) psychology's field of observation is shared with many other sciences (such as sociology, biology, physiology, etc.). Scriven's argument is, therefore, that psychology does not have its own onto-gnosiologic ground. By closing his eyes to the distinction between objects that have the same name in sociology, psychology, and common sense, Scriven is unable to appreciate the specificity of psychology and urges psychologists to abandon their science. If successful, this would certainly be a major obstacle to the advancement of psychological research.

Intrusions of philosophy into psychology are sometimes difficult to detect. Such is the case when the reputability of philosophy of science is brought in to replace the questionability of speculative philosophy. Thus, a philosophical analysis of the process of scientific discovery (e.g., Giere 1983) is usually respected as an essay in philosophy of science. However, since empirical studies of the process of scientific discovery can be conducted by cognitive psychologists (e.g., Qin & Simon 1990), the philosophical approach should be regarded as questionable speculation. If defended persistently, this alleged philosophy of science can actually become an obstacle to psychological science.

Norman Malcolm (1964) suggested that Skinner's behaviorism is very similar to Carnap's physicalist conception of psychology. This is a curious suggestion because it promotes the negligence of empirical work (and, therefore, constitutes an obstacle to scientific psychology). It is true that Carnap (1959) presented a conception of psychology that excludes subjective phenomena as causes of behavior. Therefore, Carnap's conception is consistent with Skinner's (1977) rejection of mentalism. When compared with psychoanalytic, psychometric, cognitive, or humanist conceptions, physicalism and behaviorism have much in common. However, there is a major difference between these two psychologies: Carnap's psychology is pure philosophical speculation that has not been put to test by experimentation, whereas Skinner's psychology grew out of his laboratory work (Skinner 1938). Consequently, all the specific concepts in Carnap's psychology may or may not have empirical validity. The whole history of its experimental test still has to be written. Carnap's psychology could, in principle, become a science some day. Today, it is only an obstacle to science.

As mentioned earlier, Husserl (1965) limited himself to claiming that phenomenology complements empirical psychology. His disciple, Merleau-Ponty, went further and denied the relevance of empirical studies of perceptual phenomena. According to Merleau-Ponty, the experience of perceiving is characterized by an interaction between the object that is perceived and the subject who perceives it, so that perception can never be studied as an empirical object (Merleau-Ponty 1970). Although an honorable effort to question dogmatic empiricism is evident, it is also evident that the argument does not make sense. Indeed, if perceptual consciousness is not treated as an object, it is treated as subjectivity, as intentionality (Husserl 1977). And, then, the question at hand is whether the study of subjectivity can be objective or must also be subjective. However, as Piaget (1971) noticed very well, objectivity is the goal of every science, so that if philosophical psychology gives up objectivity, it also gives up scientificity. Naturally, people are free to give up objectivity and become artists or mystic hermits. But if they incite scientists to follow them, then they must be considered obstacles to the advancement of science.

The case of Roger Mucchielli, a French physician and philosopher, is even more curious. In his book about psychosomatic medicine (Muchielli 1961), he not only criticizes the psychosomatic science with philosophical arguments, but also argues that through philosophy he can obtain the real explanation for psychosomatic phenomena. That is, in this case the philosopher not only violated the domain of a science, but also believed to be able to produce scientific knowledge by means of philosophical reflection. Were he allowed to gather followers, he would develop a full size obstacle to the progress of physiological psychology.