Wolff's deterministic view of the world is essentially a materialistic doctrine, Lange thinks: immaterial souls are free to act how they want and their existence should thus make the world indeterministic. Now, Wolff does admit the existence of souls without renouncing his determinism, and we shall see next time how Lange reacts to this strategy.
In addition to souls, Lange sees immaterialism playing a role already in Wolff's doctrine of world, particularly in latter's notion of simple substances, which Lange interprets as essentially identical with monads of Leibniz. This is yet another point where Wolff himself is truly ambiguous. On the one hand, Wolff does note the resemblance of his simple substances with Leibnizian monads and does say that the simple substances in a sense represent the world. On the other hand, Wolff prefers to speak of elements and explains that representing is here symbolizing the interconnectedness of all things, because elements are not literally conscious of anything.
Despite Wolff's skepticism of full monadology, his doctrine of elements does satisfy some of Lange's criteria for immaterialism or idealism. Material things, Lange says, should be spatial and thus should be e.g. infinitely divisible, while Wolffian elements are not spatial and definitely indivisible. Wolffian matter is thus based on immaterial things and is therefore a species of idealism, which Lange thinks is just as bad as materialism - Wolffian philosophy is then doubly bad, because it combines both idealism (in its doctrine of simple substances) and materialism (in its doctrine of deterministic world).
Lange is clearly advocating the Aristotelian idea of matter as a undifferentiated mass, which can be carved out into different shapes, but which does not consist of independently existing units. While Wolff does accept his own idea of matter without any proper justification, Lange is equally stubborn and just states the self-evidence of his views – matter just cannot consists of something that is not matter. Lange would probably have been horrified of the modern nuclear physics, which he would have had to condemn as even more immaterial – matter consists there mostly of void together with some small points without any determinate place.
Interestingly, Lange's criticism has thus far dealt with questions that were later made famous by Kantian antinomies. Lange believes that world had a specific beginning in time and thinks that Wolff supposed it to be eternal; he holds determinism to be broken by free actions of humans and God, while he assumes Wolff to deny true freedom; and he believes matter to be infinitely divisible, while Wolff supposed it to consist of indivisible substances. Strikingly, Lange's anachronistic answer to second antinomy was diametrically opposite to others, probably because the doctrine of indivisible substances was associated with notorious atomism.
So much for Lange's views on Wolffian cosmology, next time we'll see what he thinks of Wolffian psychology.