From the viewpoint of evolution, laziness is an important feature: Evolution works most efficiently if its products provide as much as necessary, but as little as possible. An organism who has more characteristics than necessary will also consume more energy and is less likely to survive the next shortage of resources than other concurring species. Therefore each high energy expenditure must be met by an appropriate use. If not, the species must de-select the “expensive” characteristic soon enough, or else face extinction. However, this leads to the interesting consequence that existent procedures which require a high energy consumption, but already have a justified use, tend to develop further uses that can turn into huge advantages for a whole species.
This is exactly what happened to sexual reproduction. Compared to asexual reproduction, a higher energy expenditure is necessary. All sufficiently complex organisms have developed reward mechanisms which fire as soon as an organism undergoes an activity which is favorable for its surviving. If such activities require a high energy expenditure and thus a certain amount of risk at the same time, they trigger particularly strong reward mechanisms. The reward for sex is the sexual lust during intercourse and the following satisfaction upon completion. Humans and other similarly intelligent animal species have developed a further use for this reward mechanism connected to sex: Additionally to the sexual intercourse needed for biological reproduction, these life forms have another form of sex which’s aim is no longer the creation of descendents but just good feelings: casual sex. So far, large aras (a species of parrots), dolphins, elephants, and some primates such as chimpanzees and bonobos, as well as humans themselves have been observed to know the concept of casual sex.
All these life forms have a certain baseline of intelligence in common, and that they gather in social groups to live together. Sex is a lustful activity which one member can share with other members of the group. When individuals of the group have sex which they mutually enjoy, this builds bonds among the group: If an individual makes me feel good, or gives me access to positive experiences with others, I will rather support this individual in a state of distress, than another who spoils positive experiences, or even steals my food or other resources. In this way, casual sex increases the readiness of the group members to support other members in situations where these individuals cannot look after themselves. In other words, casual sex induces solidarity. Solidarity in turn makes all individuals of the group – and thus the entire species – “fitter”, meaning more capable of surviving.
If you approve of the above description of solidarity – congratulations: You have been able to instinctively understand the fairness included in this situation. This means that you are conscious of a usually unconscious evolutionary inheritance – the understanding of and the wish for solidarity. While all human individuals (with the possible exception of sociopaths) carry this piece of information within their brains, for the majority, it is dorment and therefore remains unused. As a consequence, most adult individuals again and again navigate themselves into social environments in which they are either exploited or exploit others – and don’t experience or offer true solidarity.
Since sex was no longer aimed at biological reproduction exclusively, but at solidarity among the group members, the respective species developed numerous forms of sexual intercourse which make no sense from the perspective of reproduction, and thus appear to be redundant. The most popular example is homo- and bisexuality. For reproduction, these forms of attraction and sex are irrelevant since the creation of descendants is only possible with straight sexual intercourse. From the perspective of solidarity however these are a great development: Bisexual individuals are sexually attracted to all kinds of genitals, not only to roughly one half of the population, which is why they are able to have lustful sex with most of the other group members in principle, and can therefore build more social connections for support. Purely homosexual individuals can take pressure out of the group, by being able to have lustful sex which is guaranteed not to lead to descendants. Thus the group will not get more members in times of distress while (homosexual) casual sex needed for solidarity (which is even more important in times of distress) is still possible.
The concepts of Yin and Yang evolved along with the new situation: As far as reproduction is concerned, as the seeding and life-giving principle, Yang is the part that produces sperm cells, and overcomes obstacles in order to bring its information piece to the right place in the right time. As the conceiving and transforming principle, Yin is the part that takes up the sperm cells, becomes pregnant (by combining its own information piece with the other one), and bears new life. If, however, reproduction is no longer the goal of sex, or in the case of homosexuality not even possible, to describe Yin and Yang in this way is at best obsolete and at worst the origin of huge misinterpretations of the function of human sexuality.
This change however did not modify sexual intercourse itself: The bodies, the genitals, and the biological reactions behind sexual desire stay the same, even if the result is not pregnancy. Therefore, Yin and Yang evolved toward the one characteristic which had actually changed, that is the goal of casual sex – to provide positive experiences, good feelings, sexual lust and satisfaction for all individuals involved. One part gives copulation, the other part conceives these impacts and transforms them into sexual lust, a process which is also lustful for the giving part. In this way, the giving, copulating part corresponds to Yang. And the passive part which takes up and transforms, corresponds to Yin.
Since all sexual orientations are represented, individuals with two equally shaped genitals can have casual sex with each other, in the same way that straight sexual encounters happen. Consequently, Yin and Yang cannot be attributed to certain body characteristics or genitals, but instead rely on the observation which individual is the active one and doing the copulation, and who is the receiving one enjoying the copulation.
- Man thrusts woman with his penis: man = Yang, woman = Yin
- Woman rides man, man rests under her: woman = Yang, man = Yin
- Woman fingers another woman: active woman = Yang, woman who gets fingered = Yin
- Man has anal intercourse with another man: man who fucks = Yang, man who enjoys getting fucked = Yin
However, there is still a difference between the mentioned intelligent animal species and the animal species that is humankind: While animals communicate by means of body language and some sounds, humans use verbal language to a substantially larger extent. Although with humans, nonverbal communication still transports the most information, verbal communication plays such a key role that it led to another modification of the connection between Yin and Yang and sexuality. By means of verbal language, individuals can play “games” where sexual intercourse is merely a tool to make the game more enjoying. They can negotiate rules and, with consent from all individuals involved, then act out their sexual encounter according to the negotiated rules. In this way, the above activities can be put into a completely different context.
As a reminder:
- Yin corresponds to the conceiving and transforming principle
- Yang corresponds to the seeding and (life-)giving principle
By means of verbal language, the giving part can thus not only control the physical activities, e. g. the copulation during the sexual intercourse, but also other related activities or even all possible activities in the game, depending on the negotiated rules. The giving part therefore “gives” the whole lustful scenario, and acts as a director. The receiving part not only conceives the physical activities, such as copulation, but also follows the instructions of the director – as long as they feel good – and in doing so, transforms the sexual ideas and fantasy of the “director” into real sexual intercourse which is lustful for all individuals involved. The classification system of all types of sexual games that apply the aforementioned principle is called BDSM in Eurocentric/Western culture. The application of negotiated rules and their control by means of verbal language can even turn the position of Yin and Yang around when compared to who is the giving, and who is the receiving part on a physical level.
- Man thrusts woman with his penis and “instructs” the woman how to let herself get taken: man = Yang, woman = Yin
- Man thrusts woman with his penis, while the woman “instructs” him how he has to fuck her: woman = Yang, man = Yin
- Woman rides man, man rests under her, but “instructs” her how she has to ride him: man = Yang, woman = Yin
- Woman rides man, man rests under her, woman uses the body of the man as desireful tool: woman = Yang, man = Yin
- Woman fingers another woman, grabs her and “instructs” her to go off on her fingers: active woman = Yang, woman who enjoys getting fingered = Yin
- Woman fingers another woman who “instructs” the first, how she would like to be fingered: Woman who enjoys getting fingered = Yang, active woman who fingers = Yin
- Man has anal intercourse with another man, and “instructs” him how to let himself get taken: man who fucks = Yang, man who enjoys getting fucked = Yin
- Man has anal intercourse with another man who “instructs” the first, how he would like to get fucked: man who enjoys getting fucked = Yang, man who fucks = Yin