After cosmology, Wolff turns his attention once again to human soul, and just like in his German metaphysics, he divides the topic into two parts. The book I now reading, or Psychologia empirica, concerns, as the title says, empirical psychology, which is meant to provide us with the experiential information that any theory of human soul or consciousness should be able to explain. Second part, or rational psychology, is then supposed to present the theory used for explaining the propositions of empirical psychology.
Psychology is so for Wolff an empirical science, and it is through experience that we must ascertain the existence of the very topic of psychological investigations, that is, the human soul. Wolff can finally apply the Cartesian strategy, with which he had started the German metaphysics. He begins from the rather indubitable fact that we are aware of things external to us. Note that we need not confirm that there are things outside us, just that there is this state of being conscious of them. Now, it is easy to conclude that there must also be someone who is conscious, or the ”I”.
Wolff declares that the starting point of the deduction or the state of consciousness of external things is so indubitable that psychology has as certain beginning as mathematics. Clearly, he once again does not want to say that the existence of external things is certain, but only that our consciousness of them is. Wolff thus suggests that the consciousness of external things is dependent on the possibility of being conscious of ourselves. Later on, Kant tried in his refutation of idealism, as it were, to reverse this line of thought and show that our self-consciousness is dependent on our consciousness of external things.
Wolff then defines soul as that which is conscious of itself and external things. One might wonder if Wolff is here moving to the perilous area of Kantian paralogisms. Yet, one must remember that at the stage of empirical psychology Wolff merely describes what can be experienced without committing himself to any theories explaining these experiences. Thus, Wolff can certainly assume that there is both consciousness of things and consciousness of this consciousness and that these two states of consciousness are part of same stream of consciousness. He might even have the right to call this stream soul, if he just refrains from saying that the soul is e.g. immortal and independent substance – it would be just a different name for human mind or consciousness.
A more difficult problem lies in the question about the relationship of soul and body. Like a good Cartesian, Wolff notes that soul is known before body, that is, while we can be quite certain of the existence of our soul, the existence of our body is more doubtful. One might think that this assumption relies on Kant's fourth paralogism about the supposed relationship of soul and body. Yet, when it comes to empirical psychology, Wolff even here remains within the limits of what Kant could accept. Even Kant doesn't deny that ”I am and I think I am” is far more certain that the statement ”I am a bodily being”. It is only when from these facts conclusions like ”I am not a bodily being” are drawn that philosophers stray from a safe path.
Wolff's empirical psychology is then not full of paralogisms – if these are anywhere to be found, it will be in rational psychology, where Wolff will try to explain the empirical facts of our mental life. Even so, we still have to ask whether Wolff's methodology in empirical psychology is acceptable, as even I have voiced some skepticism about it.
Now, the aim of empirical psychology, according to Wolff, lies in cognition of our own soul: cognition is here defined as nothing else but awareness or consciousness of something. The cognition of ourselves, Wolff continues, we receive through our capacity of apperception. The word ”apperception” was introduced by Leibniz, because he wanted to separate consciousness of external things (perception as such) from consciousness of oneself. Wolff follows this lead in a rather unimaginative fashion. Perception, he says, is simply representation of something, while apperception is then perception of ourselves. All perceptions involve the possibility of apperception, that is, when we observe, for instance, an apple, we can also note that we are observing this apple. Wolff just takes it for granted that this self-observation is unproblematic, without considering in Kantian manner how this self-observation takes place. Yet, despite these methodological problems, we might still accept the results of such a self-observation, just as long as we do not make any problematic inferences from them – that is, just as long as we remain at the level of empirical psychology and note, for instance, that we have memories, without stepping to the field of rational psychology by trying to explain why we can remember things.
Before moving onward to a more substantial account of capacities of human mind, I shall make a note of the structure of the book. Wolff uses the trusted notion that human mind has a cognitive and volitional part, basing even the division of the book on that presupposition. Within each major part, Wolff then differentiates between less and more clear faculties – sensory perceptions from understanding, sensuous impulses from free will. Next time, we shall be looking at the book in more detail, starting from sensation or perceptions.