But the heart asks a further moral. Though it derives satisfaction from perceiving that even features of history which seem the darkest, and moments the most perilous, bear witness to the presence of a benevolent Creator, who overrules all for the improvement of man and the progress of the church; it still claims to know what those limits are, where doubt must expire in awe, and speculation in adoration. It longs to exercise inquiry, and yet retain the Christian faith. It asks earnestly what does the history teach us concerning the doubts that are most likely to meet us in our lifetime, and what lessons are supplied by it in reference to the best mode at once of maintaining our own faith, and of leading those who doubt to the faith which we receive. The materials are supplied for an answer to these questions; probably even the materials for the final answer which the church can give to them. We venture not to utter predictions in reference to the future; but the thought is interesting and solemn, that there seems some reason to believe that the weapons which doubt on the one hand, and religion on the other, must use in the final adjudication of their claims, at least in reference to all fundamental questions, are already in men’s hands. Though our express denial that doubt perpetually recurs in cycles might cause it to be supposed that we should be inclined to anticipate the existence of future crises of faith; yet we have remarked that such crises are always produced by the opening of some unexplored field of knowledge, the introduction of a collection of new ideas or of a new spirit excited by new ideas, on subjects traversed either by the Christian religion, or by the Christian inspired books. A survey of the present state of knowledge would probably lead us to think that no field lies unexamined from which such new material can hereafter come. The physical sciences which, by the discovery of an order of nature and general laws of causation, have heretofore suggested difficulties in reference to miraculous interposition, and, by means of the discoveries in astronomy and geology, have come into conflict with the ancient Hebrew cosmogony, are not likely to suggest fresh ones distinct in kind from the past. If there be not ground for discouragement in science, nor for doubting that the present state of it, which seems to offer employment for originality of mind rather in tracking old principles into details than in ascending to new ones,(1022) is merely a temporary one, destined to pass away when some happy guess shall reveal the highest laws which now baffle inquiry; yet it is not probable that such an advance will traverse the province of religion. The survey of those regions where discovery seems most hopeful, will explain the reason of this assumption.