In an individual being, especially if its constitutive elements and its activities are manifold and complex, the term nature is sometimes applied to the collection of distinctive features, original or acquired, by which such an individual is characterized and distinguished from others. Thus it may be said it is the nature of one man to be taller, stronger, more intelligent, or more sociable than another. Nature properly signifies that which is primitive and original, or, according to etymology, that which a thing is at birth, as opposed to that which is acquired or added from external sources. But the line that divides the natural from the artificial cannot be drawn with precision. Inorganic beings never change except under the influence of external agencies, and in the same circumstances, their mode of activity is uniform and constant.
Organisms present a greater complexity of structure, power of adaptation, and variety of function.
For their development out of a primitive germ they require the co-operation of many external factors, yet they have within themselves the principle of activity by which external substances are elaborated and assimilated. In any being the changes due to necessary causes are called natural, whereas those produced by intentional human activity are called artificial. But it is clear that art supposes nature and is but a special adaptation of natural aptitudes, capacities, or activities for certain esthetic or useful purposes. If necessary conditions are realized, where the seed falls a plant will grow naturally. But the seed may be placed purposely amid certain surroundings, the growth of the plant may be hastened, its shape altered, and, in general, the result to be expected from natural activities may be modified.