G.E. Lessing wrote:If no historical truth can be demonstrated, then nothing can be demonstrated by means of historical truths. That is: accidental truths of history can never become the proof of necessary truths of reason... That, then, is the ugly, broad ditch which I cannot get across, however often and however earnestly I have tried to make the leap
In some ways this is a softball to the non-theists. Lessing applied the "ugly ditch" to Christianity, suggesting that purported historical events like miracles or the resurrection could not be used as proof in defense of Christianity. Demonstrability (which eventually translated into scientific empiricism) was impossible for the historical, thereby undermining Christianity as anything other than faith. There weren't quite the hard hits against Christianity on this thread that I was expecting.
That being said, I have recently been pondering whether Lessing's critique can now be leveled more strongly against secularism than against Christianity.
(1) Are historical events necessarily an impediment to absolute claims of truth? Is Lessing's ditch real?
Lessing does raise real problems insofar as it is impossible to recreate and thereby demonstrate historical processes. History itself is non-repeatable (despite many similar cycles). Therefore, if claims of truth are rooted in demonstration, history cannot yield claims of truth.
(2) Are post-modernists correct in claiming that particular worldviews or intellectual fields emerge primarily out of particular histories or genealogies (or as a result of these histories or genealogies)?
Scourge99 has raised the best critique of Lessing and the postmodern perspective by wondering whether Lessing falls into his own ditch. There is a sense when this might be true, but at the same time Lessing does seem to offer two forms of truth: accidental truths and necessary truths. A necessary truth is true in all situations regardless of origin, but an accidental truth arises out of historical particularity. It is true, but only because of the way that things have developed.
Lessing does not say that there are no necessary truths, and seems to consider the requirement of demonstration to be a necessary truth (that seems to be a theme around here too). What he does suggest is that accidental truths (a historical event might have been different) cannot prove necessary truths because they are contingent, and grounding the necessary in the contingent makes no sense. If Lessing undermines himself, the empiricist on this forum also necessarily undermines himself, and there is no required link between demonstration and truth.
Postmodernism contributes to things by suggesting that most (or perhaps all) fields of knowledge spring from historical situations. I consider this a valid insight. Certain thinkers, certain discoveries, certain theories all of a seemingly contingent nature lead to further discoveries, theories, or thinkers. If this is the case, the content of the thinker's theories are contingent.
(3) Does the historical embeddedness of many fields of knowledge lead to problems for the secularist? For the theist?
The situation discussed above seems to create major problems for the secular non-theist (particularly of an empiricist bent). If one accepts Lessing's claim that accidental truths or isolated, non-repeatable, non-demonstrable events of history cannot yield necessary truths, then secularists have a problem. Either all aspects of a secular worldview/paradigm outside of scientific tests cannot be considered true (and one might even argue that particular scientific paradigms are historical in nature), and therefore the secularist necessarily has an arbitrary perspective on anything beyond a general understanding of nature, or else one rejects Lessing's claims and thereby opens up the door for theism. If accidental truths of history can yield necessary truths of reason, then religious experiences or historical events like the resurrection (which are both non-demonstrable) can be grounds for a worldview just as equally as the accidental historical developments of the secular perspective can be.
The theist seems to have an additional advantage. Whereas accidental truths of history to the secularist are, in fact, accidental (there being no guiding force), accidental truths according to the theist are guided by a Personal God whose interactions in history link the "accidental" with One who works according to the purpose of necessity and necessary truth. The Christian, operating within his or her own assumptions, can endorse the historical tradition of Christianity as divinely guided and therefore linked to necessary truth, but the secularist can make no such link and so is left with arbitrary assertion and basic knowledge of science (which is available to the theist as well).
This is just what I've been pondering recently, and I look forward to an expect major challenges here as I consider whether to abandon or accept this perspective.