I have explained before that Western liberalism (let's perpetuate a solecism and call it "English liberalism") is the product of humanist Catholic and Protestant ideas at the time of the Reformation - most specifically the doctrine of things indifferent in the form put forward by Philipp Schwartzerd, another who (like myself) adopted the pseudonym "Melanchthon", and particularly as Melanchthon's ideas were developed by Hooker and Locke.
Now here is a question: As an idea that has its genesis in Christian thought, could we expect a liberal society to be sustainable indefinitely that was post-Christian? Let us set aside for now the interesting question of whether a liberal society could be constructed based on Muslim ideas. As it happens, I believe that it could, but that the liberal concept in play in such a society would be unlikely to be quite the same as Melanchthon's - it would be a new form of liberalism. Having teased you with that, let me now focus on post-Christian secularism.
The question I ask is, I think, part of a more general question about the nature of post-Christian moral and political philosophy. Is Christian morality, for example, a ladder that the post-Christian humanist can climb and then pull up behind him? Is Christianity the route by which humanism happened upon the morality it prefers, but such morality can ultimately be sustained without the theological baggage? Is one form of this ladder-pulling that, even though English liberalism is, clearly, a Christian concept in origin, we don't need the Christianity to keep it going?
I think the answer to all these questions is "No". There are many reasons for this. Not the least is that practical morality evolves through time even if theoretical morality is invariant. What I mean by this is that, even if underlying moral principles never change, the situations in which they are to be applied change constantly, and the relative importance of some principles will rise and others fall, so that even in situations that might look fairly similar, the balance of judgement might tip towards the favouring of a slightly different practical call in one generation from another. So even if the humanist inherits a set of moral codes from the Christian, the humanist will struggle to make those codes evolve as the Christian would without the Christian's continuous assistance. Why does this matter? Well, it means that without the Christian the humanist's practical morality will eventually differ considerably from the Christian's. So then he must stand or fall alone. But he cannot stand, for humanism offers us no basis for its morality being objective or eternal. The very most it can do is to appeal to moral insight - to say "Look! Just as you can see that this landscape is beautiful, so you can see that this act is right/wrong." But this means that, over time, individual humanist moralities will fracture - each humanist will have his own morality, and society will lose its anchor. We will simply cease to agree over enough that we have a common enough basis to dwell together in indifference.
To see why, remember that English liberalism is the product of a doctrine of practical indifference, not metaphysical indifference. But at some point we might resolve metaphysical disagreement over right and wrong, and so practical indifference might cease. For example, perhaps there is a period in which we differ in our view as to whether slaves can be kept, and some of us keep slaves whilst others do not. But eventually we become sufficiently convinced that keeping slaves is wrong that we ban doing so. But as humanist moralities wander, anchorless, some humanists will become convicted of the rightness of and duty to promote X whilst other humanists will become convicted of the wrongness and unacceptability of X.
Of course, Christians differ over moral questions, also (that was the essence of what got liberalism started), but they have a large body of shared views and an anchoring of those views in the Bible. What the humanist hopes is that common human nature will provide a sufficiently common basis for anchoring society. But it is by no means obvious that this is so. The notion becomes particularly threatened when those of different cultures and with different life experiences enter into society - the post-Christian secularist cannot indefinitely welcome immigration from significantly alien cultures. And thus liberalism disintegrates.
Human nature is not, fundamentally, common in the required way. We can say this definitively because of the possibility of sinning through conviction. Many people in history have been involved in human sacrifices, for example, convinced that their acts were right. Yet in Western societies we find the idea of sacrificing our own children, for example, so repugnant that we assume that it must in some way be against our nature. And so it is, in a sense - but not in the sense that we do not do it and not in the sense that we cannot believe it to be right. Other peoples eat those they capture in battle - even sometimes regarding the devouring of their foes as an honour to them. Does that seem "natural" to you? Some, even in our own society, find small children sexually attractive. Is that "against nature" or is it, instead, (as I would say) wrong?
We cannot hope for common aspects of moral instinct, corrupt and unstable as human nature is, to provide us with a robust basis for morality. Even if most of us begin looking at the world in a fairly common way, because we begin by taking benefit of a Christian heritage, in the end that common treasury is doomed to be exhausted, and moral bankruptcy and the destruction of liberalism are the only possible final destination.
Liberalism is a Christian idea. Many of you secularists enjoy the concept, and think instinctively like Christians, taking benefit from us as the moral parasites that you are. But like all parasites, you cannot survive indefinitely without your host. Think on that...
