At least since the days of Descartes the problem of the reality has perplexed philosophers. Is the world that we perceive truly real, and not a mere dream, hallusination, figment created by a powerful daemon or mere fiction fed into our brain by a mad scientist? Wolff himself notes the problem, but apparently fails to take it very seriously. Wolff simply decrees that in dreams all processes are less ordered than the truth. By order Wolff means the occurence of some similarity, that is, of a pattern or a rule, which the things follow. Ultimately the basic criterion is the principle of sufficient reason or causality: processes in dreams do not follow any causal laws.
Wolff's criterion is perhaps enough for distinguishing our usual dreams from what we happen to call reality. He is not interested of a possibility that a new, even more real world might be discovered beyond the world of experience. This might be a consequence of Wolff's pragmatic nature – after all, there has to be some limit for the demand of indubitability. Furthermore, Wolff could continue, if we some day discover that we have been dreaming all along, at least this discovery will be made through the very same criterion of the regularity of processses. Here Wolff is once again paving the way for German idealists, who also had some doubts about the need to find any ultimate reality beyond the world of experience.
In modern analytic philosophy one is accustomed to mean by truth a characteristic of propositions, beliefs etc., while here Wolff essentially refers by truth to the reality. Furthermore, he almost instantly extends the notion of truth to apply to all sorts of processes. Truth thus becomes a quantifiable characteristic: the more regular and law-governed a thing is, the truer it is.
Wolff also introduces the notion of perfection (Vollkommenheit), which he then immediately characterises as a coherence of a manifold, which is yet another form of regularity in addition to truth as a regularity of processes. The regularity in its various guises appears then to be the primary value characterising simple things: the goal the finite simple things try to acheive is the regularity both in their internal processes and in the system of things they causally engage with.
Like with truth, Wolff also suggests that perfection is a quantifiable characteristic. Indeed, he appears to suggest that there could be a calculus of perfections for counting from individual perfections the quantity of their combination. Yet, the value of this combination is not a simple sum of the perfections, because one must also take into account how well the perfections fit together. For instance, the perfection of a house is not to be determined by its beauty and its utility, but one must also consider how well the beauty and the utility serve one another.
A complex thing with several constituent perfections might not then be perfect as a whole, if the perfections clash with one another. Similarly, harmony of apparent imperfections can produce a greater total perfection. It takes no Leibniz-scholar too see where this line of reasoning is heading to – we might indeed live in the best possible world, although its individual elements might seem quite unpleasant.
Before moving to the next issue, I will shortly recapitulate what Wolff has to say about the division of things. We have essentially three possible types of entities. Firstly, there are the complex finite things, and we know from experience that they exist all around us. Indeed, the whole world is a complex of all finite things. Then there are the finite simple things, and we know that at least some of them must exist – otherwise we wouldn't have even complex things to discuss about. Furthermore, although we do not yet know it, our own soul will also probably be finite, but simple. Finally, there might be an infinite thing, although we do not yet know whether there is any actual infinite thing – if there is, it will play the traditional role of God. Thus, even in his ontology Wolff has preliminarily outlined the three other parts of metaphysics: cosmology, psychology and theology. Next time, we shall move to the more concrete parts of Wolffian metaphysics.