In achieving its ascendency and unfolding its meaning, the Idea of Progress had to overcome a psychological obstacle which may be described as THE ILLUSION OF FINALITY.
It is quite easy to fancy a state of society, vastly different from ours, existing in some unknown place like heaven; it is much more difficult to realise as a fact that the order of things with which we are familiar has so little stability that our actual descendants may be born into a world as different from ours as ours is from that of our ancestors of the pleistocene age.
The illusion of finality is strong. The men of the Middle Ages would have found it hard to imagine that a time was not far off in which the Last Judgement would have ceased to arouse any emotional interest. In the sphere of speculation Hegel, and even Comte, illustrate this psychological limitation: they did not recognise that their own systems could not be final any more than the system of Aristotle or of Descartes. It is science, perhaps, more than anything else—the wonderful history of science in the last hundred years—that has helped us to transcend this illusion.
But if we accept the reasonings on which the dogma of Progress is based, must we not carry them to their full conclusion? In escaping from the illusion of finality, is it legitimate to exempt that dogma itself? Must not it, too, submit to its own negation of finality? Will not that process of change, for which Progress is the optimistic name, compel "Progress" too to fall from the commanding position in which it is now, with apparent security, enthroned? [words in Greek]... A day will come, in the revolution of centuries, when a new idea will usurp its place as the directing idea of humanity. Another star, unnoticed now or invisible, will climb up the intellectual heaven, and human emotions will react to its influence, human plans respond to its guidance. It will be the criterion by which Progress and all other ideas will be judged. And it too will have its successor.
In other words, does not Progress itself suggest that its value as a doctrine is only relative, corresponding to a certain not very advanced stage of civilisation; just as Providence, in its day, was an idea of relative value, corresponding to a stage somewhat less advanced? Or will it be said that this argument is merely a disconcerting trick of dialectic played under cover of the darkness in which the issue of the future is safely hidden by Horace's prudent god?