As is well known in philosophy [n.b. - this is a very brief summary!], Plato referenced two distinct realities, the world of things (where we live), and the world of the forms (the "true" or "pure" reality). For him, the particular "thing" in our reality is just a copy, or shadow, of the universal form, which is THE real thing. Aristotle came along and said: No, the universal is in the particular; in other words, the true reality of the thing is found somehow within the form of the thing itself. This relationship between the "universal" and the "particular," or some version thereof, has been debated ever since: Is the particular a reflection of, and thus less real, the universal, or, is the universal in the particular, tacitly making the universal dependent upon the particular?
Christianity, it seems to me, has posited a reality that is a combination of, and yet transcends, both of these options: The universal (God) is both in a particular (Jesus) and beyond all particulars. All created reality is not only a shadow of reality as it should/will be, but in some sense all particulars are contained in the universal (i.e. sustained by God’s Spirit). So, we have a dialectical relationship between the particular and the universal, one that creates an aporia for human thought.
Hegel’s attempts, as I understand him, to parse out this aporia by way of a philosophical system, finally led to his subsuming all particulars into an inevitable universal that fulfills all particularities. Kierkegaard, of course, clearly preferred the particular individual over the universal, for a variety of reasons, yet he also recognized the ultimate paradox of Christ as both universal and particular (see SK's Training in Christianity for instance). Postmoderns (or so it is often claimed) tend to think - radicalizing Kant - that since the universal is unknowable, all we have is the particular, which means that all knowledge and experience of reality is tentative and potentially meaningless.
But Christianity, again, seems to indicate NOT that we have no universal, but that the universal cannot be known directly; therefore, we need to focus on the particular, and perhaps, in examining the particular, we will grasp a small piece of the universal. At the same time, it claims that these particulars actually reflect a universal reality that is greater than, or "more real," than our own.
Now, what should our response be, as believers in the Christian reality? Some suggest that we simply have no choice but to trust God (the universal) as revealed, and make no claim to have any additional resources. Others argue that if we look at multiple particulars (I will tentatively label this approach "natural theology"), perhaps the overall effect will be that we establish some glimpse of the universal that can be employed in our attempts to function within this reality.
This leads to a host of questions, of course – How many particulars are needed to establish a pattern for the universal? Are some particulars more reliable than others? Who decides? What do we do when communities disagree over the particulars, or patterns of particulars? Is this even appropriate for Christianity, given that we already have THE supposed particular truth, namely, the revelation of Jesus Christ attested to in Scripture? Should we simply rely on that particular for guidance? What happens when that particular breaks down vis-a-vis our reality? Do we then retreat into "non-realism" or do we move into another mode of response? All these questions, and more, are related to theological reflection on the concepts of the universal and the particular...