The complexity of human society does not make it unintelligible, not even when it is a society torn by contradictions and in the process of collapse—unless one views the collapse without the benefit of philosophy. Such a procedure means: viewing the symptoms of a disease without knowing that they are symptoms, or that they have a unifying cause.
The metaphysical implications of this view is that reality is so constituted that it is explicable by an ultimate cause. Indeed, this is one of the more controversial implications behind the Objectivist view of knowledge as hierarchical. Reality conveniently allows itself to be explicable within a hierarchy of concepts, with the widest concepts explaining all the lower concepts in the hierarchy. Objectivism tries to evade these metaphysical implications by insisting that this hierarchy is purely epistemological. But in the form it takes in the Objectivist philosophy of history, it is unclear that the metaphysical implications can be carelessly swept under the epistemological rug. Peikoff assumes that as long as you view the complexity of human society with “the benefit of philosophy,” it must be intelligible. Every symptom, Peikoff assumes, has an identifiable unitary cause. This assumption cannot be made on epistemological grounds alone. Unless one assumes that reality itself in fundamentally intelligible, Peikoff’s epistemological assumptions are entirely gratuitous.
The trouble with these unstated metaphysical implications is that they are not fully consistent with realism, that is to say, with the belief in an external substantive world existing in its own plane, with a movement, origin, and destiny of its own, apart from what we may think or fail to think of it. Peikoff’s argument for a single cause of history implies that reality must be intelligible—as if reality exists or was created for our personal cognitive convenience. That is not an assumption the truculent and uncompromising realist can ever make. “A really naked spirit [i.e., a mind without a priori presuppositions] cannot assume that the world is thoroughly intelligible,” wrote one such truculent realist, George Santayana. “There may be surds, there may be hard facts, there may be dark abysses before which intelligence must be silent, for fear of going mad.” At most, the intrepid realist can only assume that reality is partially intelligible, that it is say, that we can know what is necessary for our survival and genetic reproduction. Whether the rest of reality is intelligible can only be discovered empirically; it cannot be assumed a priori.