The naturalistic fallacy is to identify what is with the good – or to confuse how things are with how things should be. That is to read axiological values from ontology. This may be associated with phrases such as 'the natural order' and 'that's nature's way'.
So, for example, someone born into a society with slavery or extreme unequal distribution of wealth and power might assume this was the 'natural' social order. In nature, it is very common in many species for only a minority of individuals to live to maturity; and for any individual who is deformed or badly injured and so cannot respond sufficiently to critical challenges (weather, predators, hunger) to be allowed to quickly die. This does not mean that this is how ethical agents (such as humans) should organise society.
