“Que baita livrão” é o que eu tenho a dizer sobre “Sapiens – A Brief History of Humankind”, do historiador israelense Yuval Noah Harari. Passei vergonha lendo e me dando conta do meu minguado conhecimento sobre… Tudo. Um exemplo: eu sempre achei que os humanos evoluíram de forma linear – tipo, o Homo Ergaster evoluiu para o Homo Erectus, o Homo Erectus evoluiu para o Homo Neanderthal, o Homo Neanderthal evoluiu para o Homo Sapiens. NOPE! Há 100 mil anos, pelo menos seis espécies diferentes de humanos caminhavam ao mesmo tempo pela Terra! E: quando o Homo Sapiens chegou ao Oriente Médio e à Europa, a região já era habitada por Neanderthals. O que aconteceu com eles? Por que desapareceram do planeta? Harari escreve (tradução livre): “A tolerância não é uma marca registrada do Sapiens. Em tempos modernos, uma pequena diferença de cor de pele, dialeto ou religião é suficiente para levar um grupo de Sapiens a tentar exterminar outro grupo. Será que os Sapiens antigos seriam mais tolerantes com uma espécie humana completamente diferente? É bem possível que, quando os Sapiens encontraram os Neanderthals, o resultado tenha sido a primeira e mais significativa campanha de limpeza étnica da história”.
Eu tinha separado vááárias aspas para o caderno de quotes de livros, mas como a maior parte delas depende do contexto de um capítulo inteiro, vou listar apenas esta “pequena” passagem de uma página e meia:
“Culture tends to argue that it forbids only that which is unnatural. But from a biological perspective, nothing is unnatural. Whatever is possible is by definition also natural. A truly unnatural behavior, one that goes against the laws of nature, simply cannot exist, so it would need no prohibition. No culture has ever bothered to forbid men to photosynthesise, women to run faster than the speed of light, or negatively charged electrons to be attracted to each other.
In truth, our concepts ‘natural’ and ‘unnatural’ are taken not from biology, but from Christian theology. The theological meaning of ‘natural’ is ‘in accordance with the intentions of the God who created nature’. Christian theologians argued that God created the human body, intending each limb and organ to serve a particular purpose. If we use our limbs and organs for the purpose envisioned by God, then it is a natural activity. To use them differently than God intends is unnatural. But evolution has no purpose. Organs have not evolved with a purpose, and the way they are used is in constant flux. There is not a single organ in the human body that only does the job its prototype did when it first appeared hundreds of millions of years ago. Organs evolve to performe a particular function, but once they exist, they can be adapted for other usages as well. Mouths, for example, appeared because the earliest multicellular organisms needed a way to take nutrients into their bodies. We still use our mouths for that purpose, but we also use them to kiss, speak and, if we are Rambo, to pull the pins out of hand grenades. Are any of these uses unnatural simply because our worm-like ancestors 600 million years ago didn’t do these things with their mouths?
Similarly, wings didn’t suddenly appear in all their aerodynamic glory. They developed from organs that served another purpose. According to one theory, insect wings evolved millions of years ago from body protusions on flightless bugs. Bugs with bumps had a larger surface area than those without bumps, and this enabled them to absorb more sunlight and thus stay warmer. In a slow evolutionary process, these solar heaters grew larger. The same structure that was good for maximum sunlight absorption – lots of surface area, little weight – also, by coincidence, gave the insects a bit of a lift when they skipped and jumped. Those with bigger protusions could skip and jump farther. Some insects started using the things to glide, and from there it was a small step to wings that could actually propel the bug through the air. Next time a mosquito buzzes in your ear, accuse her of unnatural behavior. If she were well behaved and content with what God gave her, she’d use her wings only as solar panels.
The same sort of multitasking applies to our sexual organs and behaviour. Sex first evolved for procreation and courtship rituals as a way of sizing up the fitness of a potential mate. But many animals now put both to use for a multitude of social purposes that have little to do with creating little copies of themselves. Chimpanzees, for example, use sex to cement political alliances, establish intimacy and defuse tensios. Is that unnatural?” (p. 147-148)