When discovering facts about the world, there is one method that is proven to work, and only one. It is usually called the scientific method, but it might more properly be called the modern method. It consists of discovering evidence, reasoning from that evidence to a conclusion or general principle, and then submitting both the evidence and the argument to the review of our peers, so that any flaws can be picked out and critiqued. This is the method we attempt in our science, our courts, our journalism, our history, our politics, and in any other area where we need to understand facts about the world.
This approach is now under attack from two directions: pre-modern understandings of the world, which include religion and old folk tales, and post-modern philosophies, by which all models of the world are equally valid. Post-modern arguments are now enlisted to defend pre-modern opinions--in the absence of absolute certainty, post-modernists have made the colossal mistake of assuming that nothing is true, and that all opinions are equal--leaving the field open to pre-modern opinions, not only of religions, but of other pre-modern cultures.
Although Marx made critiques of capitalism that cannot be ignored (or that we ignore at our peril) he also set the stage for post-modernism, with the idea that claims about social relations are not objective, but are always made in the context of the existing political economy, and are therefore relative to the current status quo. But his attack was only upon dominant opinions concerning social relations, which are aggregates of subjective opinion. It has no bearing upon facts. My pen in on my desk, and this fact falsifies all opinions which hold that my pen is elsewhere. Post-modernism jumps from the subjective to the objective, and from the denial of Truth with a capital T, to all truth. Their claim upon Marx as the father of this folly is almost entirely without basis, except that he seems to imply that there is nothing about human social relations that are matters of fact and not subject to revision (a public denial which will, I believe, bury Stephen Jay Gould's reputation in ignominy.) This is the basis of the nature vs. nurture debate, in which Marxists resolutely deny all influence of nature, genetics, evolution, or inborn talent or proclivity. Indeed, this is an attitude which persists across the entire left, which makes them blind to a number of social challenges. Try to talk to someone on the left about the uneven distribution of intelligence, and you will meet a brick wall. In an information age, in which everyone is expected to adapt to rapidly changing job requirements, how can you possibly address the problem of the permanently disenfranchised if you do not come to grips with this? What happens to the ditch diggers, the farm hands, the street sweepers, when all of these jobs are replaced by a man who must be smart enough to run an expensive machine that replaces them all? And so the most burning question of our age will be ignored by the right, who have no interest in solving it, and by the left, who have no interest in addressing it.
This blurring of subjective opinion and objective fact is encouraged by both religions and political ideologies, who find themselves in an empirical deficit, and seek to undermine the very standards of truth to get a free ride. The problem is particularly acute for theologians, whose discipline evinces all the trademark symptoms of an art, rather than a domain of knowledge: endless branching, proliferation, varying styles, forms, schools, a cacophony of opinions without recourse to any means of resolution, with many theologies beginning with outright contradictions, upon which anything can be proven. Certainly there are clever reasonings; Russell's proof that he was the pope, from the premise that 1 = 2, was a flash of brilliance, but utterly fallacious for all its genius, as Russell made clear. The faithful aren't stupid, but their intelligence yields only elaborate rationalizations, not truth. The problem, for theology, is made worse by the absence of any method of resolution. But as Orwell made so clear, without truth or a method to establish it, there is only the boot forever stamping on the human face. This is the Triumph of the Will; without reason and evidence, without truth, there is only force. Religion has no recourse but the boot. And it will always seek the power to stamp out its opposition.
Our modern habit of reasoned discussion and resolution is not shared by advocates of pre-modernism and post-modernism. They believe that there is no method leading to truth, and all opinion is established by force, and must be changed by force. The political correctness they advocate is enforced by the power of the police. The likes of Stanley Fish are court jesters who have long since ceased to amuse, perpetual adolescents under the protection of a king they no longer serve. Not Lear's fool, who spoke truth to power, but a populist fool who does not believe in truth.
If the protection of modernity were ever removed from these fools, they would be consumed by the chaos they invoke. Unfortunately for us, and fortunately for them, they are protected from that by the defenders of modernity, who know very well that there is nothing but the boot for those who abandon it.