Georg Bilfinger hasn't really struck me thus far as an original thinker, and indeed, many of his writings have been mere summaries of theories belonging to other philosophers. Hence, I did not have high expectations of Bilfinger's metaphysical work, Dilucidationes philosophicae de Deo, anima humana, mundo, et generalibus rerum affectionibus. In fact, the very first pages felt very familiar: the division of metaphysics into ontology, cosmology, psychology and natural theology has been used already by Wolff, and even many of the doctrines readily reveal the philosophical allegiances of Bilfinger. Because Wolff's other student, Thümmig, had already latinized Wolff's philosophy, Bilfinger's motives for publishing his own work appeared confusing.
Even so, Bilfinger's work feels somewhat more substantial presentation of Wolffian philosophy than Thümmig's summaries, and surprisingly, often manages to round even the discussions of Wolff himself. One clear reason is Bilfinger's habit of expounding opinions of previous thinkers, which was something sorely lacking in Wolff's texts. This does not make Bilfinger's work a mere redundant repetition of familiar ideas, but allows him to engage in a fruitful philosophical discussion. Bilfinger was a man of compromises, and Kant later adopted in his early work Bilfinger's suggestion that one should always try to reconcile opposing views by finding out what is good in both of them.
Good example of Bilfinger's abilities is his theorizing on modalities, that is, notions of possibility, impossibility, necessity and contingency. While Wolff was content with just one definition of e.g. possibility, Bilfinger starts with several definitions and notices interesting relations between them. In addition to Wolffian definition that possibility means lack of self-contradiction, Bilfinger considers the explication that possibilities are something inherently potential in other things. This second notion of possibility is clearly dependent on actuality in the sense that nothing could be possible in this sense, if there were nothing actual: there couldn't be any potential, if we had no source for such a potential.
Now, Bilfinger notes rather ingeniously that if some preconditions hold, the two notions of possibility coincide. Clearly, potentialities must also be non-contradictory. Furthermore, if we have an entity with infinite powers, it will obviously have the capacity to produce anything that is not inherently contradictory: thus, the extension of the two concepts of possibilities coincide. Bilfinger can so explain reasonably why e.g. Wolff did not notice or at least ignored the crucial distinction: he accepted the existence of God and did not therefore need to consider the second form of possibility.
Just like possibility is not a single concept for Bilfinger, similarly impossibility isn't either. Of course, there is the absolute impossibility of contradictions like round square, but there's also contextual impossibility, where a certain thing or person is incapable of doing something. Furthermore, this incapacity might be proper or due to a lack of power, but there are also important cases of improper incapacities. Firstly, Bilfinger thinks that the general incapacity to change past is an improper incapacity: it's just the nature of past to be completely determined. Secondly, an even more important type of incapacity concerns moral issues. Thus, God could well have created quite a horrible world, full of torture and grief, in the sense that he has the necessary power for doing this, but because of his infinite goodness, he doesn't have the moral possibility for doing this – a distinction clearly influenced by the need to defend Wolff against the suspicion of determinism.
It is in making these clarifications and in pointing interesting problems where Bilfinger's worth really lies. Some of these are familiar already from Wolff, like Bilfinger's notion that a sufficient reason does not need to necessitate an action, because of the freedom of agents, or his idea that imperfection might be just contextual. I shall thus proceed by picking up one important point in all of the four major divisions in Bilfinger's work. As I've already noted an important ontological statement of the plurality of the concepts of possibility, I shall next time plunge in cosmology and ask what sort of validity physical laws are supposed to have.