Aside from Herbart’s textbook presentation of traditional logic (e.g., Section II of LEP), his main logical innovation is his so-called method of relations, devised as an organon for correct metaphysical thinking (SW V: 201, f.). The metaphysical problems it aims to address include: the thing as (one) substance with (many) characteristics; causality; matter; and the ego. He considers these problematic because they give rise to an empirically given, yet self-contradictory concept (Weiss 1928: 37). Due to space constraints, we will here only briefly touch on the problems of thing and ego, the former for its role in the development of apperception, the latter because it is grounds his psychology. Both his idea of metaphysics and the method of relations will become clearer as we see them used to explain concrete psychological phenomena in Section 3.
The problems of both thing and ego may be stated thus: there is a conflict between an alleged unity, on the one hand, with an empirically manifest plurality, on the other. We consider a thing to be one substance, yet possessing a number of conflicting qualities; and we regard the self as a single entity conscious of many thoughts. But is the thing the one, or its many qualities? Is the self or psyche the one, or its thoughts? Herbart maintains that this dilemma arises due to a missing link, one that can only be supplied by “speculation”. Speculative use of the method of relations would have us consider the conflicting elements not as distinct entities in genuine opposition, but rather as members of a unifying relation. For example, the “thing” turns out to be the nexus or system of (its) predicates, and nothing else beyond them (cf. Beiser 2014: 118). Similarly, Herbart regards the psyche not as a substance, but simply as the condition of mental change itself.
He follows Kant in distinguishing between conscious phenomena and unknowable noumena that must be conceived as underwriting the coherence that experience finds in the fluctuating phenomenal manifold. The noumena are “speculative”, by which Herbart does not mean objects of intellectual intuition, but rather the transcendental conditions of the synthetic unity of objects of experience. Yet where Kant held noumena to be unknowable, Herbart takes the further step of ascribing to every existent “an act of self-preservation”, a notion as opaque as it is important to his psychology (SW II: 195). The idea seems to be that every being must have an inherent force holding it together, or there would be no reason to suppose its continued existence: “the idea of a force to maintain one’s identity” just is “self-preservation” (Beiser 2014: 120).
In short, the method of relations is a way of doing metaphysics with strong Platonic and Kantian overtones: the fluctuating and conflicting plurality of sensible experience is “related” back to intelligible, “speculative” unities that allow us to organize the plurality in experience. Thus, the method does more than merely analyze contradiction; it also resolves them by supplying the intelligible links. We will take these points up in more detail as they arise in Herbart’s psychology.