The definition of ethical fitnessism can be found in “Ethical Fitnessism. The Ethic of the Fittest Behaviour”, which is mainly in Swedish but there is an English abstract. In the abstract you find the definition:
…the ethic whose behaviour tends to be maximized as a consequence of natural selection.
Exactly which behaviour that is is a scientific question. Dawkins's central theorem of the extended phenotype:
An animal’s behaviour tends to maximize the survival of the genes ‘for’ that behaviour, whether or not those genes happen to be in the body of the particular animal performing the behaviour. [Dawkins, 1982, The Extended Phenotype, Oxford University Press, p. 248]
seems to suggest that the behaviour which is maximized is the behaviour which follows the following rightness criterion:
An action is right for an individual if and only if the action maximizes the survival of the genes for this individual’s behaviour.
Of course this is up for debate and further scientific research is necessary. There is no disagreement, I think, that animals are adaptation-executers, but still natural selection will favour certain behaviour over other behaviour. It is also evident that evolution by no means leads to perfection, for example we have vestigiality.
The focus of ethical fitnessism is not survival of the individual, but the survival of the behavioural genes of the individual, not short term but in endless time. Since most individuals share behavioural genes to a great extent with other individuals there are good reasons for not causing harm to related individuals. If I had the option to sacrifice myself for the guaranteed continued survival of humanity and its successors for millions of years I would do so and I believe that natural selection would favour such a behaviour.
A strong argument for ethical fitnessism is that by definition natural selection will cause organisms to tend to act according to ethical fitnessism. Fitnessist behaviour will out-compete other behaviour, such as for example the behaviour that hedonistic utilitarianism promotes. This means that hedonistic utilitarian behaviour in the long run cannot survive in a system affected by natural selection. But the argument doesn’t end there. Let us ask ourselves what behaviour conscious beings will believe is right to perform. That natural selection would favour conscious belief in a behaviour which is distinctly different from the behaviour which the organism is actually performing, seems unlikely. Most probably natural selection favours conscious belief in the behaviour which the organism is actually performing.
A strong argument for ethical fitnessism is that by definition natural selection will cause organisms to tend to act according to ethical fitnessism.
Err... no.
Organisms do not act according to ethical fitnessism -- you define fitnessism as whatever behaviour was picked by natural selection. Accordingly, there is no "strong argument", it's just the definition of your neologism.
Fitnessist behaviour will out-compete other behaviour
No, because if you're looking backwards in time, conditions change and what used to be adaptive might be counterp...
I noticed that there has been some earlier discussion about Sam Harris’s Moral Landscape Challenge here at LW. As a writer on the Swedish politico-philosophical blog The Inverted Fable of Reality, I would like to share a response to the challenge, written by our main contributor, which I believe is interesting to read even if you are not familiar with The Moral Landscape or its content. See this link for the response and a short explanation of the challenge.
The response takes a different approach to most responses to the challenge. It is divided into four parts and starts by asking which ethic is most compatible with science and reality and finally tries to answer this question.