Neo-vitalism, on the other hand, is, at least, an attempt at solving the problem in the positive sense. It ascribes the unique activities of living organisms to the operation of a superphysical and superchemical energy or force resident in living matter. This unique dynamic principle is termed _vital force_. It is not an entitive nor a static principle, but belongs to the category of efficient or active causes, being variously described as an agent, energy, or force. To speak precisely, the term agent denotes an active being or substance; the term energy denotes the proximate ground in the agent of a specific activity; while the term force denotes the activity or free, kinetic, or activated phase of a given energy. In practice, however, these terms are often used interchangeably. Thus Driesch, who, like all other Neo-vitalists, makes the vital principle a dynamic factor rather than an entitive principle, refers to the vital principle as a “non-material,” “non-spatial” _agent_, though the term _energy_ would be more precise. To this active or dynamic vital principle Driesch gives a name, which he borrowed from Aristotle, that is, _entelechy_. In so doing, however, he perverted, as he himself confesses, the true Aristotelian sense of the term in question: “The term,” he says, “... is not here used in the proper Aristotelian sense.” (“History and Theory of Vitalism,” p. 203.) His admission is quite correct. At the critical point, Driesch, for all his praise of Aristotle, deserts the Stagirite and goes over to the camp of Plato, Descartes, and the Neo-vitalists!