When I look at the massive collection of Wolff's combined works, I get the impression he might have been a keen business man: after all, it requires a good sales pitch to get one's writings sold numerous times after the first print. Furthermore, it is not just the huge amount of reprints, which makes me consider the possibility, but also the fact that Wolff essentially made duplicated copies of his works in German and Latin. The most astonishing example is still Wolff's logic. The German version of logic was one of Wolff's first publications, but so fond of the topic Wolff was that he essentially summarised the main ideas of the book in his German metaphysics and especially in psychological chapters (after all, cognition is part and parcel of human mental life) and then years later in his book on morals (naturally, a moral person has a duty to find out as reliable information as possible). It is once again the point coinciding with logic I have now hit on Wolff's Latin psychology. Since I have so recently went through Wolff's Latin logic in quite a detail, I shall just do a quick summary of Wolff's ideas of intellect and cognition, especially from a psychological point of view.
Last time I described Wolff's notion of intellect as a faculty of distinct ideas. Although one can have distinct ideas of individual objects, it is especially universalities Wolff is interested here, because universalities are an essential ingredient in the more complex forms of intellectual cognition, that is, making judgements and reasoning on basis of judgements. I also noted Wolff's distinction between intuitive cognition based on direct observation of ideas and symbolic cognition based on language and generally signs and their manipulation. Wolff notes that this duality continues throughout all levels of cognition. Thus, we can have direct awareness of a universal feature shared by a number of entities or we can just refer to this feature with a general word, we can note a connection between certain ideas of universal features of we can express this connection with a string of words and we can use the connections we have observed to deduce more connections or we can use formal rules of syllogism and mechanically calculate consequences of certain linguistic expressions.
The capacity to draw inferences Wolff calls reasoning, and it is closely related to the faculty of reason, which is just the capacity to view a whole system of universal truths and their interconnections. The more pure a reason is, the less external material it has to use, and pure reason would observe a system based only on definitions and self-evident axioms – note that Wolff does not indicate what sciences actually belong to pure reason, but one would assume that at least mathematics is a part of it.
Pure reasoning is then expectedly a form of a priori cognition. In Latin logic Wolff made it clear that actually all cognition uses reasoning a priori, that is, also deductions based on experiences. Here Wolff also explains that all cognition based on experiences is a posteriori, thus making it possible that cognition is both a priori and a posteriori – this is what Wolff calls mixed cognition. Wolff is thus beginning to approach a position in which a priori and a posteriori refer to components and not types of cognition. We might also note that Wolff divides experiences and says that a posteriori cognition can be based on active experiments and passive observations, which includes in addition to sensuous perceptions also apperceptions, thus making psychology explicitly not part of pure reason.
We might finally point out that Wolff introduces the notion of an analogy of reason, which was especially important to Wolff's followers, such as Baumgarten. Wolff's idea appears to be that as the ideal of reason is a system of interconnected truths, we might expect that world conforms to this system in the sense that it is also a system of interconnected entities. Thus, if some part of nature is known to be structurised in a certain manner, we have a justification to assume that some similar part of nature is also structurised in the same manner.
So much for theoretical part of the soul, next time we'll start to tackle the practical side of our nature.