The central feature of the new realism was a rejection of the epistemological dualism of John Locke and the older forms of realism. The group maintained that when one is conscious of, or knows, an object, it is an error to say that there are two distinct facts -- knowledge of the object in a mind, and an extra-mental object in itself.
In an example from Edwin Holt: the question between the old realism and the new concerns knowledge that a particular cow is black. Is the blackness on that cow's hide, or in the observer's mind? "That color out there is the thing in consciousness selected for such inclusion by the nervous system's specific response,"Holt wrote.
Consciousness, in the sense Holt has in mind here, is not physically identical with the nervous system which is the condition of selections. The consciousness is "out there" with the hide of the cow. Consciousness is all throughout the field of sight -- and smell, and hearing -- for which the nervous system selects. For consciousness is at any moment identical with the set of facts it is said to know.
This position belongs to a broader category of views sometimes called neutral monism or, following William James, radical empiricism. But it hasn't worn well over the subsequent century, in part because of the quandary that resulted when its practitioners had to consider abstract ideas, such as blackness. Here, it seems very natural to locate the abstract idea in my head, and to justify it by its utility in dealing with the world. The extra-mental world includes cows, and dark nights, and pirate flags. Blackness as an abstraction is a mental tool for dealing therewith.
But that analysis was not available to the new realists, who did not want to acknowledge representational ideas at all. The nervous system is merely a system of selection. So, the idea of black must be out there, in something of the same manner as is the cow or the pirate flag, to be selected.
Generally speaking, the new realists saw this necessity and embraced something akin to Aristotle's form of realism -- black is something that the pirate flag and the hide of the cow have in common, and the nervous system selects not just those things but that commonality as a fact in the world. This runs into difficulties, though, as Arthur Lovejoy showed in his book, "The Revolt Against Dualism."
The perception of black is so dependent on context, in the visual field, in the perceivers' personal histories, and in the cultural usage of the term, that it just doesn't work to try to reduce it all to the commonalities within the objects to which we apply the word. Better, Lovejoy thought, to bring representational ideas back into the account after all.