or causal force by which an object is made suitable to its end. For example, did I wish to give a student a general notion of a man, I should say: Man is (1) the chief creation of God, and destined for dominion over other creatures; (2) endowed with freedom of choice and action; (3) and on that account provided with the light of reason, that he may direct his choice and his actions with wisdom. This is but a general notion of man, but it goes to the root of the matter and says everything about him that is essential. To these you may, if you like, add some of his accidental qualities, still keeping to generalities, and this must be done by asking the questions from what origin? whence? when? You may then proceed to his parts, the body and the soul. The nature of the body can be demonstrated through the anatomy of its organs; that of the soul by examining the faculties of which it consists. All these points must be taken in their proper order.
20. (vi) All the parts of an object, even the smallest, and without a single exception, must be learned with reference to their order, their position, and their connection with one another.
Nothing exists in vain, and sometimes the strength of the larger parts depends on that of the smallest. Certain it is that in a clock, if one pin be broken or bent, or moved out of its place, the whole machine will stop. Similarly, in a living body, the loss of one organ may cause life to cease, and in a sentence it is often on the smallest words, such as prepositions and conjunctions, that the whole sense depends. Perfect knowledge of an object can therefore only be attained by acquiring a knowledge of the nature and function of each of its parts.
21. (vii) All things must be taught in due succession, and not more than one thing should be taught at one time. The organ of vision is unable to take in two or three objects at one time (certain it is that he who reads a book cannot look at two pages at once, nay, cannot even see two lines, though they lie quite close together, nor two words, nor two letters, otherwise than successively); and in the
