We must, then, in order to believe, understand what it is that is told us; but it is by no means necessary that we should understand how it is to happen. It is not necessary, and in a thousand instances we do not know. "If we take poison, we shall die:" there is a statement which we can understand, and therefore believe. But do we understand how it is that poison kills us? Does every one here know how poisons act upon the human frame, and what is the different operation of different poisons,--how laudanum kills, for instance, and how arsenic? Surely there are very few of us, at most, who do understand this: and yet would it not be exceedingly unreasonable to refuse to believe that poison will kill us, because we do not understand the manner _how_? Thus far, I think, the question is perfectly plain, so soon as it is once laid before us. But the real point of perplexity is to be found a step further. In almost all propositions there is something about the terms which we do understand, and something which we do not. For instance, let me say these few words:--"A frigate was lost amidst the breakers." These words would be understood in a certain degree, by all who hear me: and so far as all understand them, all can believe them. All would understand that a ship had sunk in the water, or been dashed to pieces; that it would be useful no more for the purposes for which it had been made. But what is meant by the words "frigate" and "breakers" all would not understand, and many would understand very differently: that is to say, those who had happened to have known most about the sea and sea affairs would understand most about them, while those who knew less would understand less; but probably none of us would understand their meaning so fully, or would have so distinct and lively an image of the things, as would be enjoyed by an actual seaman; and even amongst seamen themselves, there would again be different degrees of understanding, according to their different degrees of experience, or knowledge of ships, or powers of mind.