What criticisms did Friedrich Adolf Trendelenburg make of Hegel’s logic?

Friedrich Adolf Trendelenburg presented a significant critique of G.W.F. Hegel’s logic in his Logische Untersuchungen (1840), primarily arguing that Hegel’s system relied on hidden, non-logical assumptions.1

Trendelenburg’s criticisms focused on two main points:

• The Spurious Beginning: Hegel claimed his logic began "without presuppositions," moving from Being to Nothing and then to Becoming. Trendelenburg argued this movement is actually dependent on the surreptitious presupposition of empirical motion. Without this external support, the transition between these concepts cannot be logically justified.1
• Confusion of Contradiction: Trendelenburg charged that Hegel conflated logical opposition (the contradiction of A against non-A) with real contrariety (the opposition of A against B). He argued that logical contradiction is merely a formal repetition with a negative sign, from which no concrete movement can arise. Conversely, real contrariety involves elements that must be derived from empirical experience. Trendelenburg concluded that Hegel mistakenly treated intrinsically real contraries as if they were abstract, logical contradictories, thereby building his system on an arbitrary dialectic.1