If a man is really laid under a necessity of sinning, it would certainly seem impossible to conceive that he is responsible for his sins. Nay, it would not only seem impossible to conceive this, but it would also appear very easy to understand, that he could not be responsible for them. In order to remove this difficulty, and repel the attack of his opponents, Calvin makes a distinction between “co-action and necessity.” “Now, when I assert,” says he, “that the will, being deprived of its liberty, is necessarily drawn or led into evil, I should wonder if any one considered it as a harsh expression, since it has nothing in it absurd, nor is it unsanctioned by the custom of good men. It offends those who know not how to distinguish between necessity and compulsion.”(2) Let us see, then, what is this distinction between necessity and compulsion, or co-action, (as Calvin sometimes calls it,) which is to take off all appearance of harshness from his views. We are not to imagine that this is a distinction without a difference; for, in truth, there is no distinction in philosophy which may be more easily made, or more clearly apprehended. It is this: Suppose a man wills a particular thing, or external action, and it is prevented from happening by any outward restraint; or suppose he is unwilling to do a thing, and he is constrained to do it against his will; he is said to labour under compulsion or co-action. Of course he is not accountable for the failure of the consequence of his will in the one case, nor for the consequence of the force imposed on his body in the other. This kind of necessity is called co-action by Calvin and Luther; it is usually denominated “natural necessity” by Edwards and his followers; though it is also frequently termed compulsion, or co-action, by them.