性行为的类型

人们毫无例外地都知道人在睡眠时有体验性反应的能力。可是，在特定的文化和历史时期，人们只认为男人才有这种能力。例如，《圣经》告诉我们在古希伯莱书里，一个在睡眠中有性高潮的男人必须去为净化而施洗礼。他无意中的射精被称为“污点”，使他变得“不干净了”[《利未记》(圣经《旧约全书》中的一卷)第15章；申命记(旧约全书中的一卷)第23章]。而女人没有与男人可比的条件。因为她们不会射出任何东西，人们并不关注她们的自发性高潮。

可是，在中世纪，随着人们再一次相信古代人所笃信的夜魔的存在，这种局面略有所改变。那时，人们把性梦归于魔鬼的出现，既有躺在男人身下的女魔鬼(被称为女妖)，也有卧在女人身上的男魔鬼(被称为恶魔)。这种猜想后来于15-17世纪在“寻找”和迫害“女巫”中起到了重要的作用，这是一连串令人压抑的群体歇斯底里和人类荒唐的历史事件之一。

恶魔 中世纪书籍插图 Incubus Medieval book illustration

It has always been well known that human beings are capable of experiencing sexual responses while they are asleep. In certain cultures and historical periods, however, people ascribed this capacity only to males. For example, the Bible tells us that, among the ancient Hebrews, a man who had an orgasm in his sleep was required to take a ritual bath for purification. His involuntary ejaculation of semen was called a "pollution" which made him "unclean" (Leviticus 15; Deuteronomy 23). There was no comparable requirement for women. Since women do not ejaculate anything, nobody paid any attention to their spontaneous orgasms.
However, this changed somewhat in the Middle Ages with a revival of ancient beliefs in nightly demons. Sexual dreams could now be ascribed to visits by the devil who appeared either in the form of a woman, lying under a man (a so-called succubus) or as a man, lying on a woman (an incubus). This idea later played an important role in the “discovery” and persecution of “witches” in the 15th - 17th centuries, one of the most depressing episodes of mass hysteria and human folly.