From our earlier remark that the science of ethics is primarily concerned with what _is_ rather than what _ought to be_, it may be difficult to imagine what place the concept of human freedom can have in a mechanistic treatment of the problems of conduct. It might seem easier to foreshadow what will be the fate of the concept of obligation, especially when we realize that oughting is always hypothetical, rather than categorical. For every obligation is specific and particular,—it depends upon conditions, places, times, and persons, just as does every signification of good and bad, and right and wrong. There is no general Ought, as our recent discussion of Kant’s categorical imperative clearly implied. When, then, we ask from whom or from what obligation arises, what answer does a mechanistic ethics provide? Some may expect us to make the traditional answer, namely, that it comes from the group, and that the _feeling_ of obligation is a variation of the elemental type of conscience. This sort of an answer is not to be given here. Although the group largely determines how we shall feel with regard to what _ought_ to be done, yet the final education of an ethically adult person leaves him with a different mind on this point. Indeed, it is our purpose here not only to show that the concept of ethical freedom is a valid concept for a mechanistic ethics, but also and more particularly that a true conception of ethical obligation depends upon the discovery of what ethical freedom implies. That this involves no paradox will be understood as soon as we comprehend what it means to say that a man is _free_. Herewith we shall state five conditions under which freedom of action is guaranteed. The first meaning of free action is _action that is physically possible_. I am not now, I never was, and I never shall be free (that is, able) to walk backward and forward at the same time, or to be in Boston and New York simultaneously. Neither can I, while kissing Jennie at her fireside, be also kissing Kate at her doorway a mile from Jennie’s house. On the other hand, the man who is sound of limb, sensorially acute, and otherwise endowed with natural capacities, can be said to be free to employ these capacities whenever and wherever the conditions provide the opportunity.