And, first, I observe that mysteries are _necessary_ attendants on religion. There can be no revelation without them. There can indeed be no knowledge without them. To a little child the earth is a plane of no great extent, and the stars are colored lamps hung in the canopy of the night. But as he grows older, he learns that the earth is very big, and that the stars are very far off, and that there are many systems of worlds above us; and now how many questions press themselves upon his mind! What is the history of this universe? How old is the earth which we inhabit? Are the stars inhabited? Science with the hard earnings of human thought and labor gives him some little satisfaction, but for every question that she sets at rest there are many new ones that she raises, and at last in every department there comes a point where she gropes, and loses her way, and stops altogether. If you light a candle in a large room it casts a bright light on the table you are sitting at, and on the pages of the book you are reading, but gives only a dim light in the distance. You see that there are pictures on the walls, but you cannot discover their subjects. You see there are books on the shelves, but you cannot read their titles. When the room was quite dark you did not know that they were there at all, and now you know them only imperfectly. So every light which knowledge kindles brings out a new set of mysteries or half-knowledges. For this reason it is that a man of true science is apt to be modest in his language. Your loud-talking philosopher, who has no difficulties, has but a very narrow scope of thought and vision. He is clear because he is shallow. But a highly educated man _knows_ that there are a great many things he is ignorant of, and so his language is modified and qualified. {401} I believe it was Sir Isaac Newton who used to say, that in his scientific investigations he seemed to himself like a child gathering pebbles on the sea-shore. It was his vast attainments that made him sensible that Truth is as boundless as the sea. And when scientific men forget this; when they forget how much they are ignorant of; when they are boastful, over-positive, or inconsiderate in their statements, how applicable to them becomes the reproof which the Almighty addressed to Job: "_Where wast thou when I laid the foundations of the earth? tell Me if thou hast understanding. Upon what are its bases grounded? or who laid the corner-stone thereof? By what way is light spread, and heat divided on the earth? Who is the father of the rain, or who hath begotten the drops of dew? Dost thou know the order of heaven, and canst thou set down the reason thereof on the earth? Tell Me, if thou knowest these things_."