From Dualism to Postmodernity

This sounds remarkably like an essay topic assigned to a class by someone who has recently read A Primer on Postmodernism by Stanley J. Grenzà

As I'm sure you are aware, there are many forms of dualism (e.g. metaphysical, epistemological, anthropological, etc.). I suspect that the context in which this question arose will imply one or more of those forms.

Anthropological body-soul dualism is perhaps the form that most often bears the unqualified label "dualism." Is this the type to which the question refers? In body-soul dualism, it is generally argued that the body is bad and that the soul is good. It is frequently put forth that salvation includes, among other things, freeing the soul from the body. While this view is still present in the world, and unfortunately even in the church, it is probably not as prominent as it once was.

The question, however, seems to assume that the demise of dualism has been recent (it assumes that this demise produced or significantly influenced postmodernism). I'm not sure I agree with this premise. At least by the time of the Enlightenment, the western world had begun to move away from the idea of the supernatural. In so doing, they necessarily abandoned the traditional view of anthropological dualism. In some cases, they replaced it with mind-body dualism, but this view is still common (i.e. it has suffered no demise).

Also, it is not at all apparent to me that dualism met any particular crisis in the collapse of modernity, or even that we may speak of modernity as no longer present. Certainly the world and church are still full of modernists. Further, I fail to see how modernism was particularly friendly to traditional forms of dualism (e.g. body-soul - modernism tended to deny the soul). Moreover, Postmodern thought may be the popular philosophical trend of the day, but it is not, in my assessment, a majority viewpoint.

It seems to me that the question assumes a dualism in modernity that in my estimation is not terribly evident or central, and that it assumes a rejection of dualism in postmodernism that is not really legitimate. Postmodernism does emphasis a holisitic perspective, but this is not so much a rejection of dualism as it is a rejection of the reductionism and feigned unaffectedness of modernistic thought.

About the only kind of dualism that I can imagine would really characterize modernism in some sense and be rejected by postmodernism is Descartes' subject-object dualism, wherein because the self is the thinking subject, everything else in the world is perceived as an object. This radical distinction between self and other is an inherent aspect of the modernistic assumption that the scientist/observer/whatever may be unaffected by his environment and subject of study. Postmodernism by and large rejects this view (its relativistic view of truth arguably leaves some room for the view in certain cases). In this sense, Postmodernism follows Heidegger more than it follows Descartes. I'm afraid, however, that I cannot trace for you the history of Descartes' dualism, or connect it somehow to classical forms of dualism.

On the Christian response to the Postmodern context, we have a good article on our site by Jules Grisham, entitled A Re-Presentation of Reformed Theology. Though it is geared toward Reformed Theology as opposed to the more narrow subject of the gospel, it makes many points that apply equally to both subjects.

I would also suggest that if you have access to the book I mentioned at the beginning of this answer (Grenz, Stanley J. A Primer on Postmodernism, Wm. B. Eerdmans, 1996), you check out pp. 84-88 (on subject-object dualism) and pp. 161-174 (on the gospel in a Postmodern context).