Kant's error about rational psychology: Psychical appearance and reality
by Titus Rivas (*)
'Who forces us to think that subjectivity is real, essential?'
Friedrich Nietzsche, Der Wille zur Macht
'The reality of a sensation is exhausted by its appearance to us; for sensations, esse is percipi.'
Anthony J. Rudd, What It's Like and What's Really Wrong with Physicalism
In this essay I defend Karl Popper's position that the negative evaluation of 'rational psychology' by the German philosopher Immanuel Kant forms the main implicit basis for the present acceptability of the identity theory in the philosophy of mind. Furthermore, I claim the Kantian analysis cannot stand critical scrutiny. I will finally show what this means for the philosophical status of the identity theory.
1. Kant and rational psychology
In his well-known Kritik der reinen Vernunft Immanuel Kant intended to show that the pretensions of the metaphysics of his own era (and even metaphysics in general in the traditional sense) were groundless. He wrote that all our knowledge is relative to certain unchangeable, given suppositions of human perception and reasoning. We have no access to reality as it is in itself -an sich-, but only to reality as it appears to us through our specific human filters of perception and thought. Therefore, we can never hope to reach any insight in the true nature of things. The only attainable goal we can reasonably long for, is to reach knowledge of how things are and behave within reality as it appears to us.
Gary Hatfield states: "Although other modern philosophers before Kant, including Descartes, Locke, and Hume, had conceived of the project of examining the knower and the knower’s cognitive capacities, Kant’s investigation stands apart because he provided a novel and an especially thorough examination of the powers and capacities, or “faculties,” of the human mind, which he explicitly linked to determining the very possibility of metaphysics. Moreover, Kant’s conclusions differed significantly from those of his predecessors. His so-called “deduction” of metaphysical concepts claims to justify the use of such concepts, but it justifies them differently than would either a rationalist or an empiricist. This deduction also put limits on the use of these concepts, of a kind that would undercut rationalist metaphysics. Like Descartes, Kant thought that metaphysics could provide a systematic body of theoretical first principles, but he denied that it provides knowledge of substances as they are in themselves."
Kant used a specific terminology to distinguish the traditional metaphysical and the empirical objectives. Metaphysics is traditionally searching for knowledge of noumenal reality, i.e. of reality as it really is, independent of any human presuppositions or cognitive deformations of perception and thought. Empirical science, however, strives for knowledge of phenomenal reality, i.e. the world as it appears to us humans.
Within the metaphysics of Kant's days there was a branch named 'rational psychology' which may legitimately be compared to our own contemporary philosophy of mind. As a subspecies of metaphysics, Kant criticized the rational psychology of thinkers like Wolff and Leibniz and analyzed its 'paralogisms'. The main problem Kant has with rational psychology is that it tries to rationally deduce metaphysical truths about the soul, whereas all rational psychologists can logically dispose of, consists of phenomenal psychical reality. Psychical reality as it really is, noumenal psychical reality in other words, necessarily remains unknown to them. Rational psychology pretends it can deductively show the immortality of the soul, and so on, whereas according to Kant, all it can really do is give a catalogue of phenomenal truths which imply nothing for noumenal reality. (See for example the Second Book of Transcendental Dialectics.)
Thus, rational psychology fails hopelessly. We can know absolutely nothing about noumenal reality, and we can make no exception for our own conscious experiences. The Cartesian adagium Cogito (ergo) sum (the very foundation of Cartesian and Neocartesian epistemology and ontology) can only hold for my conscious existence as a phenomenon, not as a noumenon.
2. Kant's rejection of rational psychology, and identity theory
One of the main lessons Kant wants to teach his readers is that, contrary to common metaphysical doctrines, we have absolutely no knowledge of noumenal reality. For example, we don't know if anything noumenal corresponds to the phenomenon of matter. And if there is indeed something which corresponds to it, we have no way whatsoever to find out what it is. Similarly, what phenomenally appears to be mind, might in noumenal reality be something entirely different.
I hope that the epistemological correspondence between this Kantian position and the modern position about the ontology of mind called 'identity theory', is quite clear. Both Kantian and modern identity theory distinguish between mind as it appears to us, from a first person perspective ('by acquaintance'), and mind as it is in in itself. Mind can be considered both from a subjective and from an objective position according to both theories. (Addition of July 2004: Wolfgang Gasser has kindly written me that Kant did not use the word objective as a synonym for noumenal and reserves the term for the context of 'phenomenal objectivity', but the reader should know that I here use the word in a more general rather than specifically Kantian sense.)
It is hardly surprising therefore if Karl Popper (1977) traces the identity theory back to Kant via Schopenhauer, Clifford, Schlick, Feigl and Bertrand Russell. However, there is an important difference which should not be overlooked. Kant clearly claims that we can never know the true nature of mind, only mind as it appears to us through our perceptual and cognitive filters. On the other hand, identity theory is usually certain that the true nature of mind is physical, i.e. that mind seen from an objective third person perspective is precisely the brain or part of it. Kant should doubtlessly characterize the identity theory position as a groundless metaphysical claim of a 21st-Century rational psychology.
Still, the identity theory would be nowhere if we could show Kant to be wrong in his general rejection of rational psychology. There is something paradoxical about this, because if Kant is right about rational psychology, identity theory should be seen as a form of groundless speculation, as any other type of philosophy of mind should. However, if Kant is wrong about rational psychology, this would mean we do directly know something about mind as it is, from our private first person perspectives, so that the distinction between phenomenal and noumenal underlying identity theory would collapse. Either way, within the context of an evaluation of the Kantian critique on rational psychology, immediately it becomes surprisingly clear that identity theory isn't viable (Rivas, 1996, 2003).
3. Phenomenal and Noumenal Reality of Mind
I want to defend the position that the distinction between the conscious mind as it appears to us and a noumenal conscious mind (as it would be rather than just appear) is groundless. This position can be compared to that of Franz Brentano (1973), though I doubt that he held it for the same reason. Stronger parallels may be found in Bolzano (1970), Searle (1997) and Rudd (1998).
According to Kant, we have phenomenal experiences of an external world and of our own private, psychical world. Since our acquaintance with both worlds is necessarily phenomenal, we don't know anything of those worlds in themselves. An explicit 19th-Century defender of Kantian phenomenalism of mind, was Friedrich Nietzsche, (Nietzsche, 1992, book I, 65). Not only does Nietzsche speak of the exclusively phenomenal access to our inner mental processes, but he also states that this access might even be completely ficticious, meaning that there might in fact (or 'noumenally') be no such thing as introspection or subjectivity. This mental phenomenalism is a central notion within Nietzsche's philosophy, to such an extent that much of his thought depends on it.
Now, I claim that there is a serious contradiction hidden in this assertion. Kant is certain that there really are phenomenal experiences, and rightly so. But if he is, how can he at the same time deny that we know something about our minds, namely that we have phenomenal experiences?
(Wolfgang Gasser told me in 2004 that reality is a term Kant reserved for phenomenal reality, but even if that is true, we may still ask how Kant could claim to know that all we have is phenomenal experiences of our minds so that our minds could be completely different than they appear to be.) It is contradictory to claim that all we ultimately have are phenomenal experiences of an inner and outer world, while denying at the same time that we know that those phenomenal experiences as such are part of ultimate reality. This means that phenomenal experiences as such must be real not only from a phenomenal point of view, but also in an ultimate, ontological sense. Note that I'm not just claiming this, but analytically proving my claim. If Kant's claim that we can only know the world as it appears to be, were merely a claim about knowledge in the phenomenal sense, and not about knowledge as such (as it is), this would imply that Kant invalidates his own words about the limits of our knowledge, because absolutely nothing could be known about knowledge as it is - not even about its limits - and only about knowledge as it appears to be. All his authoritative and influential claims about knowledge would become completely based on mere phenomenal appearances and imply nothing about the ultimate reality of knowledge in itself, according to the implications of his own system. Or, as
"Dietrich von Hildebrand shows that Kant's entire epistemology is problematic from the bottom up: Kant dissolves the authentic meaning of knowledge as the grasping of a being such as it is objectively . . . by replacing it with the notion of the construction of the object. We must stress again and again that this implies an immanent contradiction . . . in the interpretation of knowledge. . . . In claiming to reveal to us the real nature of knowledge, Kant presupposes the notion of knowledge which he denies in the content of his thesis."
My point here is that the conscious mind can only be conscious. It cannot ultimately be something else than itself. If we say that a conscious experience might in reality be something else than that conscious experience we are saying that the conscious experience as such might ultimately be non-conscious, which is analytically absurd. It would be like saying that we only imagine and think that we imagine and think, but that it might be the case that we actually never imagine and think anything. The contradiction is that it would require us to have only a (subjective) illusion that we truly experience things, whereas this can never be the case, as illusion is itself such an experience.
We cannot have the illusion of experiencing subjective phenomena (compare: Popper, 1977). It is only in the phenomena's possible referential characteristic of pointing at something outside themselves that we can have an illusion. Phenomena might refer to something completely non-existent or absent, as in the case of hallucination, or they might distort (information from) sensorial stimuli. But as such, phenomena cannot be mere illusions (of phenomena). Being phenomena, they necessarily are what they seem.
Kant therefore made a very serious mistake in his evaluation of rational psychology. Whereas it is logically thinkable that the outside world is not what it seems, it is simply inconceivable that the world of phenomenal experiences - the conscious mind - would be anything else than itself. In phenomenal life, the life of "how things appear to us subjects", the distinction between a phenomenal experience as it appears and a phenomenal experience as it is, cannot be made. Therefore, we do ultimately have direct access to our own phenomenal experiences. We experience them as they are, not just as they appear. Their appearance is their reality. Appearances as appearances are always those very same appearances. In other words: The objective -in the usual non-Kantian sense of this word- (an sich) nature of subjectivity is subjective. David J. Chalmers (2003) has formulated this as follows: "If something feels conscious, it is conscious. One can hold more generally that the primary and secondary intensions of our core phenomenal concepts are the same."
Thus, it is Descartes or even the ancient scholars, like Plato and Plotinus, that should from now on form the historical basis for the ontology of mind, not Kant's error of analysis.
4. Identity theory and Kant's error
Kant has made an unfortunate error in analyzing rational psychology. He thought that consciousness as it appears and consciousness as it is could be two different things. The same errors occur in identity theory as we have seen. Thus, Feuerbach says (p. 168): "(...) from the fact that thought is not a brainprocess to me, but an act which differs from the brain and which is independent of it, it doesn't follow that it is not in itself a brain process. No, on the contrary: What to me or subjectively is a purely spiritual, immaterial, non-sensuous act, is in itself or objectively material, sensuous. The identity of subject and object (...) particularly concerns the brain process and the process of thought" (Thies, 1975).
The implication is obvious: If Immanuel Kant can be said to go astray in this respect, the same must go for identity theory. In other words: The conscious mind cannot really be the unconscious brain. What if we consider the other possibility, namely that the brain is the phenomenal appearance of the 'noumenal' reality of consciousness? According to Karl Popper (1977), this would be what Feigl thinks, so that Popper considers him more of a spiritualist than a materialist. The answer is that only if the brain as a material object is a phenomenal illusion and exists only as that illusion, it would be possible to consider it as really (and exclusively) a part of the mind. The point is that ontologically speaking we would then have a type of idealism, not of identity theory. Popper mentions that Feigl wishes to be seen as a materialist.
5. Is introspection infallible?
Does the foregoing imply that introspection must be infallible? Is it not obvious that we can be wrong about past subjective experiences or about the best way to categorize them? There are two different definitions of the term introspection involved here. In the sense of direct acquaintance with our subjective experiences as they are, introspection must necessarily be infallible. In the sense of the correct categorization of subjective experiences, or of knowledge of our personal psychological history, development or mechanisms, introspection is certainly fallible. The quality of fallible introspection in the second sense is directly dependent on the infallible introspection in the first sense.
Summing up, we can say that the ontological identity theory is a contradictory position based on the untenable notion of two perspectives from which one would be able to consider the conscious mind. The only viable road to the conscious mind is the subjective one. The conscious mind is not really something physical. The objective perspective on the conscious mind is the subjective perspective.
Now, if we wish to cling to a notion of matter as a noumenon, the only possible ontology for contemporary philosophy of mind can be a form of radical dualism (Smythies & Beloff,1989). The only alternative would be an idealism which rejects the 'real' (ultimate), i.e. non-mental existence of matter (Foster, 1991) .
Obviously, this has important implications for the ontological foundation of psychical research.
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(*). I wish to thank Vincent Pompe, John Beloff, René van Hezewijk, Rob de Vries, Anthony J. Rudd, Sandy Lemberg and Anny Dirven for their useful suggestions. I'm also grateful to Ms. Elena and Katerina M. for their moral support when I wrote the first draft of this paper (early 1990s). I'm indebted to Wolfgang Gasser for his comments on the first version of this online paper.
This paper is mentioned on this website.
This paper has been published several times on the internet, and the present version dates from 2012.