Eugenics arose at a time when the pace of evolution was unknown. Charles Darwin himself thought it was a very slow process. But many of his admirers believed it went at breakneck speed. Considerable hereditary changes were believed to take place in just a couple of generations. (No, they don’t.) Hence the myth that the social problems could be solved by breeding.
Ideas of breeding were based on a faulty analogy. A population with predicable characteristics was desired by eugenicists. Something like that is beneficial when cultivating annual plants. Same applies to domesticated animals used for a specific purpose. The downside is plants and animals being vulnerable to changes. To a long-lived species like humanity homogeneity would be counterproductive. You never know which characteristics will be useful later. Moreover, most human characteristics which can clearly be discerned are inherited in an unpredictable way. To the extent they are even hereditary.
Eugenicists as a rule took it for granted all kind of things were hereditary. Many such characteristics have later turned out not to be so. Take for example mental retardation which is rarely hereditary. Most such cases are caused by birth trauma. Mental retardation was lumped together with epilepsy and psychoses. Epilepsy is not hereditary. The potential to develop a psychosis is at least partially this. However, not even then is it a matter of “like begets like”. Not to talk about the maladjustment originating in horrible upbringing conditions. This and coincident physical weakness were misunderstood as bad genes. People believed their descendants were doomed to go extinct. But their currently living descendants rarely have even one of their ancestors’ various problems. The environment creating that combination has simply disappeared.
Some eugenicists seem to have believed in a general hereditary superiority. Physical fitness was mixed up with surviving contagious diseases. The capacity for all they believed they could see in newborns. Some maintained that babies with low birth weight should be left to die! As if this single characteristic would be able to predict such. We could probably agree one should not do so. There is a correlation between physical performance and resistance to diseases. However, this is about nutritional status and not generally good genes.
Many different anatomical traits were associated with mental characteristics. Something taken much advantage of was the precise shape of the head. There are small differences in how elongated the skull is. Some of these differences I can see with my unaided eye. Such are naturally hereditary. Otherwise, there would not be differences between different parts of the world. The very most of indigenous Europeans are in the middle of the normal range of variation. So people were divided by on which side of the centre line they were. The trouble is what happened when the standard of living rose. Children born after this differed on this level from their own parents. Differences subtle enough are as such not hereditary.
There was a widespread belief in the myth of a pure-bred human population. (Nowadays it is only racists claming anything such.) An ethnically homogenous countryside population was supposed also be genetically homogenous. The first to come along was supposed to be typical for an arbitrarily chosen home district. Some individuals made maps with fields in different patterns. These were claimed to show the extent of various anatomical traits. When I see such maps I only see random variation. The borders of the differently patterned fields reflect the mental categories the author had. In contrast they don’t reflect any real barriers for gene flow. Which they were wrongfully believed to do.
Not only is a genetic homogeneity within ethnic groups a myth. Real barriers for gene flow have turned out to be rare. Instead, the commonness of genes varies very gradually by geography. People which grandparents were born in places close to each other are more genetically similar. This too applies to traits of appearance to the extent they are hereditary. Differences between various ethnic groups are as such only statistical. Some characteristics are more common in some ethnic groups. It is never that virtually everyone of an ethnicity has it.
Passing on of hereditary diseases they were wrong about too. The existence if hidden hereditary characters was initially unknown. There are few hereditary diseases requiring only one gene. These are new mutations. Or they are not noticeable until after most have already had children. Otherwise, they would quickly disappear by natural selection. Most hereditary diseases require two copies of the gene. The combination is not inherited together but requires one copy from both your mum and dad. So if you only has one copy the gene is not noticeable. Some traits of appearance are inherited this way too. These don’t have to be visible in the parents for you to inherit them.
This type of hidden hereditary characters was paid attention to on the early 20th century. But then the eugenicists did not consider this. They continued to argue as if all hereditary characters are noticeable. Eugenicists believed they could be eradicated by forcibly sterilising individuals with unwanted characteristics. As if the characteristics themselves were inherited instead of hereditary characters for them. There are genes which in double copies makes the person having them sterile. If forced sterilisation worked would not such have disappeared?
Genes does not always need to be good or bad. Some characteristics can be beneficial in various physical environments. In other physical environments they are to the opposite harmful. Others has both upsides and downsides. Much indicates psychoses are the price humanity pays for the ability of creativity. Not because creative people necessarily have psychoses. But because several genes contribute to both conditions. In some combination they make the person creative. In other ones they give potential to develop a psychosis. So we can’t get rid of psychoses if we want to keep our creativity.
Uploaded on the 19th of June 2025.
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