In a critique of legal positivism, the main argument (for or against) is the positivist doctrine of separation between law and morality, whereas the naturalist believes the law can only be looked at from a moral standpoint. This is the defining point between a positivist and a natural law theorist.
A positivist (no matter which "strand" of positivist) argues that law and morality should in no way be connected. There should be a definite distinction between the two. There are many reasons for this division - but essentially it allows society to function by law alone - giving individuals the option of their moral beliefs. That is, positivists argue that if morals and law are connected, then the legislators (who would somehow be morally superior) determine the morality of those in society who function with those laws, and thus prevent freedom of mind and choice. .
However, Davies makes it clear that it just simply isn't possible to separate law from morality entirely. She says "clearly positivism isn't separate from the social individual, since it is inevitably such beings who constitute, decide and administer it". Positive law reflects social and political interest - and thus somewhat reflects morality. The legal process is connected to human choice, which is inevitably a moral choice. She says it is not possible to have both objective knowledge and application of it, and achieve a just social ordering, because the decision makers" - the legislators and judges - make laws and decisions which are designed around their moral bias. Thus, she points out, the eventual product is the creation of a classist society - because the class, gender, race and culture of the people making the decisions (basically white, Western men) will control the laws that are made - and hence reflect their morals, regardless of the separation of law and moral belief. .
The positivists argue that separation is between the individual morality and law - legislators take upon a "legal personality" (which Davies describes as an "abstract" theory) .