Now let us go a step further. There are two ways in which the human machine goes wrong. One is when human individuals drift apart from one another, or else collide with one another and do one another damage, by cheating or bullying. The other is when things go wrong inside the individual when the different parts of him (his different faculties and desires and so on) either drift apart or interfere with one another. You can get the idea plain if you think of us as a fleet of ships sailing in formation. The voyage will be a success only, in the first place, if the ships do not collide and get in one another’s way; and, secondly, if each ship is seaworthy and has her engines in good order. As a matter of fact, you cannot have either of these two things without the other. If the ships keep on having collisions they will not remain seaworthy very long. On the other hand, if their steering gears are out of order they will not be able to avoid collisions.