If we want to insist that the world around us is fully material, then we can't represent it; and if we want to insist that it's fully immaterial, i.e., the product of pure mind, or soul, then that world can't be represented either. In both cases the all important subject-object dichotomy breaks down and we find ourselves in the quesionable world of metaphysical presence*.
Le Fanu claims that he wants to see the world as a "duality," in which both the immaterial world of the mind and the material world of the brain are independent of one another. But his notion of "duality" requires a complete rethinking of evolution along lines that clearly favor the former at the expense of the latter. In other word, the "duality" he argues for is really not a duality at all, but a realm in which the most important and challenging problems of evolution must be guided by vaguely defined, but for him essential, immaterial forces. So what he is really arguing for is a monism, in which the material world is ultimately the product of the mind.
What's important to understand, as I see it, is that neither the purely material (i.e., scientific) nor the purely immaterial (i.e., spiritual or mental) view is fundamentally wrong. Both views oppose one another, but at the same time, both have to be correct (since there is no other alternative). And not only relatively correct, but profoundly correct. The impossible position I am describing here could be called "radical dualism." Not to be confused with the so-called "dualism" espoused by Le Fanu, in which the scientific view is rejected in favor of a type of spiritualism. Nor should it be confused with the approved "scientific" position, in which the mind is reduced to a secondary effect of the brain. Nor should it be confused with the Hegelian dialectic, in which an apparent contradiction is resolved on a "higher" level. There is no higher level on which such a fundmantal contradition can be resolved. It is in fact not simply a contradiction, but an aporia, i.e., a fundamentally unresolvable dilemma, literally an impasse.
But how can we think such an impossible thing? Fortunately, we have a powerful precedent for dealing with an aporia of this kind, which has already arisen in the realm of physics, specifically quantum theory. For a long time it was assumed that light, like sound, took the form of waves, and this became the basis for just about all research in this area throughout the nineteenth century. Early in the Twentienth Century, however, it became evident through research by Einstein, among others, that light could also be understood in terms of discrete particles, or photons -- i.e., "quanta" of light. So what was light, really: waves or particles? Further research determined that neither interpretation could be falsified -- that both must be true.
It was the genius of the physicist Neils Bohr, in my opinion one of the greatest philosophers who ever lived, which recognized that the so-called wave-particle duality (or, more accurately, aporia) was fundamentally a problem of representation. According to Bohr,
There is no quantum world. There is only an abstract physical description. It is wrong to think that the task of physics is to find out how nature is. Physics concerns what we can say about nature.(to be continued . . . )
* ". . . in truth the loss of what has never taken place, of a self-presence which has never been given but only dreamed of and always already split, repeated, incapable of appearing to itself except in its own disappearance." Jacques Derrida