What does the author mainly try to convey in the passage?

Directions: Read the following passage and answer the question.
It is admitted that at a hasty glance, there may certainly seem some danger of our faith in life's value collapsing, together with our belief in God. It is admitted that this is not in the least irrational. But it is contended that a scientific study of the past will show us that these fears are groundless, and will reassure us as to the future. We are referred to a new branch of knowledge, the philosophy of history, and we are assured that this will set all our doubts to rest. This philosophy of history resembles the practical wisdom learnt by the man of the world. As long as a man is inexperienced and new to life, each calamity as it comes to him seems something unique and overwhelming, but as he lives on, suffers more of them, and yet finds that he is not overwhelmed, he learns to reduce them to their right dimensions, and is able, with sufficient self- possession, to let each of them teach some useful lesson to him.
Thus, if we were not better instructed, we might naturally take the present decline of faith to be an unprecedented calamity that was ushering in an eve of darkness and utter ruin. But the philosophy of history puts the whole matter in a different light. It teaches us that the condition of the world in our day, though not normal, is yet by no means peculiar. It points to numerous parallels in former ages, and treats the rise and fall of creeds as regular phenomena in human history, whose causes and recurrence we can distinctly trace. Other nations and races have had creeds, and have lost them; they have thought, as some of us think, that the loss would ruin them: and yet they have not been ruined. Creeds, it is contended, were imaginative, provisional, and mistaken expressions of the underlying and indestructible sense of the nobility of human life. They were artistic, not scientific. A statue of Apollo, for instance, or a picture of the Madonna, were just representations of what men aimed at producing on earth, not of what actually existed in heaven, and if we look back at the greatest civilizations of antiquity, we shall find, it is said, that what gave them vigor and intensity were purely human interests: and though religion may certainly have had some reflex action on life, this action was either merely political or was else injurious.
It is thus that intense Greek life is presented to us, the influence of which is still felt in the world. Its main stimulus we are told was frankly human. It would have lost none of its keenness if its theology had been taken from it. The same holds true now. And there, we see the positive worth of life; we see already realized what we are now growing to realize once more. Christianity, with its supernatural aims and objects, is an ‘episode of disease and delirium;’ it is a confusing dream, from which we are at last awaking.