446. (ii) Sexual love starts when a youth begins to use his own intellect to think and act, and his speaking voice begins to show male characteristics.
This point is made in order to make it known that the stage at which sexual love and thus fornication start is when the intellect begins to become rational of itself, to investigate, that is, and seek out what things are beneficial and useful. The basis for this is then provided by the memory of the teachings of parents and instructors. At that time the mind undergoes a change. Previously thinking had been restricted to matters committed to memory, mulling them over and obeying them. Afterwards thinking is controlled by reasoning about these matters; and then, under the guidance of love, the matters retained in the memory are re-arranged, and he begins to live his own life in accordance with their new order. By stages his thought becomes more and more controlled by his own reason, and he is free to exercise his will.
It is well known that sexual love follows the emergence of a person's own intellect, and develops in keeping with its vigour. This is an indication that this love increases as the intellect develops and decreases as it declines. By increasing we mean acquiring wisdom, by declining lapsing into folly. It is wisdom to restrain sexual love, folly to give it wide scope. If it leads to fornication, which is the start of its activity, it needs to be controlled by the principles of decency and morality which have been implanted in the memory and so the reason, and must later be implanted in the reason and so in the memory. The reason why when a person's intellect begins to develop, the voice begins to become a man's is that the intellect thinks and expresses its thoughts in speech. This is an indication that it is the intellect which makes a man, and also his masculinity. As a result, he becomes an adult and also a male, as his intellect is raised (see above 433, 434).