The double degree of the theoretical activity, æsthetic and logical, has an important parallel in the practical activity, which has not yet been placed in due relief. The practical activity is also divided into a first and second degree, the second implying the first. The first practical degree is the simply _useful_ or _economical_ activity; the second the _moral_ activity. Economy is, as it were, the Æsthetic of practical life; Morality its Logic. [Sidenote: _The economically useful._] If this has not been clearly seen by philosophers; if the correct place in the system of the spirit has not been given to the economic activity, if it has been left to wander about in the prolegomena to treatises on political economy, often vague and but little developed, this is due, among other reasons, to the fact that the useful or economic has been confused, sometimes with the concept of the _technical,_ sometimes with that of the _egoistical._ [Sidenote: _Distinction between the useful and the technical._] _Technique_ is certainly not a special activity of the spirit. Technique is knowledge; or rather, it is knowledge itself in general which takes this name when it serves as basis, as we have seen it does, for practical action. Knowledge which is not followed, or is supposed not to be easily followed by practical action, is called "pure": the same knowledge, if effectively followed by action, is called "applied"; if it is supposed that it can be easily followed by a particular action, it is called "applicable" or "technical." This word, then, indicates a _situation_ in which knowledge is, or may easily be, not a special form of knowledge. So true is this, that it would be altogether impossible to establish whether a given order of knowledge were, intrinsically, pure or applied. All knowledge, however abstract and philosophical it may be believed to be, may be a guide to practical acts; a theoretical error in the ultimate principles of morality may be reflected and always in some way is reflected in practical life. One can only speak roughly and unscientifically of certain truths as pure and of others as applied. The same knowledge that is called technical may also be called _useful._ But the word "_useful_" in conformity with the criticism of judgements of value made above, is to be understood as used here in a verbal or metaphorical sense. When we say that water is useful for putting out fire, the word "useful" is used in a non-scientific sense. Water thrown on the fire is the cause of its going out: this is the knowledge that serves for basis to the action, let us say, of firemen. There is a link, not of nature, but of simple succession, between the useful action of the person who extinguishes the conflagration and that knowledge. The technique of the effects of the water is the theoretical activity which precedes; the only useful thing is the _action_ of the man who extinguishes the fire.