Philosophy approaches the subject of sex, marriage, love, and celibacy in a perfectly sane and rational way, but without the limitations and without the ignorance of a merely materialistic rationalism. Consequently, it grades the counsels which it gives on two levels.
It is not concerned with the average man who is not particularly interested in more than an average good life within the fold of conventional aims and needs.
The first level is for the beginning quester who has set his aims and needs somewhat higher than the average man and who is willing to undergo a moderate discipline for this purpose.
The second is for the more advanced quester who seeks to attain the highest possible standard and who is willing to pay in self-denial and self-training the corresponding price.
The beginner's counsel allows him a disciplined sex life, with the extent of the discipline being set by himself, for no general rule which would cover the widely varying circumstances, responsibilities, obligations, and characters involved can possibly fit them all. It explains the nature of the sex force and then leaves it to him to decide how far and how fast he wishes to go with its control.
The second grade counsel is almost monastic in its disciplinary demand for it bids him refrain from the sex relation altogether, save for the purpose of having children, whose number must be limited and proportioned strictly. In the case of the unmarried, there will then be a complete chastity.
No counsel can be given to the attained philosopher, for since he is able to reabsorb the sex urge successfully, completely, spontaneously, and unconsciously there is no urge, desire, or passion felt in this direction at all. Consequently, there is no need here for any kind of discipline. Nevertheless if, being married, he should decide to have children there is equally nothing to stop him from entering into the sexual act for this purpose. When that happens it will not be at the bidding of any lower urge, but out of willingness to provide a physical vehicle for the high-grade ego or egos he, and his wife, expect to attract.
-- Notebooks Category 5: The Body > Chapter 7: Sex > # 1