It is human nature to eat when you are hungry, to drink when you are thirsty, and to sleep when you are tired. Nothing can alter this least of all socialists. However, what is meant by human nature as an objection to socialism, is not human nature at all, but human behaviour. Human behaviour roots are to be found principally in one's environment and the economic conditions which influence one's physiological make-up. Man behaves in the way he does, very largely, although not completely, because of the conditioning he receives from his environment since he is a social animal and lives in a community. How we behave is not "innate" or governed by our "instincts" or our genes, but can and does vary depending on the sort of society we were brought up in and live in.
We are born human and therefore possess the unique capacity to adapt culturally in accordance with the environmental conditions which surround us. The brain is not just a passive receptor of sense-impressions (experience) but plays an active role in organising these impressions so as to make sense of them (understand them). This capacity to organise sense impressions is part of human biological nature. Before humans could develop culture – accumulated wisdom such as ways of tool making, hunting and gathering method, which is learned and passed on by non-biological means – they had to have brains capable of learning and of using language and of thinking abstractly. These brains had to have evolved and are just as much a part of “human nature” as walking upright and stereoscopic colour vision. So, there's no denial of human nature. The view that the mind is a blank sheet on which the environment can imprint anything is wrong because the brain plays a much more active role in the learning process. Nor are we born with pre-programmed patterns of behaviour. We learn how to behave after we are born (this even starts while we are still in the womb) and in so doing "programme" our brains. We are animals that are capable of adopting a great variety of behaviour patterns. The nature of our brain allows us, as participants in a particular system of society, to "programme" ourselves, in ways that neuroscience is beginning to understand in more detail, for living in that society. Human behaviour is not biologically determined and that the main characteristic of us humans that distinguishes us from other animals is the capacity, as a species, to engage in a great variety of behaviours. This versatility and flexibility when it comes to behaviour have a biological basis, of course.
There is scarcely a single socialist who has not heard repeatedly the statement that human nature is against socialism. This objection needs to be met. When an opponent of socialism says “What about human nature?”, “you can't change human nature!” Needless to say that when they talk of human nature they mean human behaviour. So when a supporter of capitalism says “you can't change human nature”, the reply should be: “who wants to? Human nature is alright as it is!”. Human nature as it is makes it possible to exist in all kinds of manifestations, not just support for capitalism but also the potentiality of the change from the behaviour of capitalism to that of socialism. The combination of our genetic and cultural characteristics makes humanity a superbly adaptable being, well-equipped to deal with problems.
For socialists, human nature is viewed as the “normal” mode of behaviour and mental outlook in any given society at any given period and, being determined by external material circumstances (physical but above all social), varied over the type of society, time and place. Human nature is not fixed, but variable. It is what we would now call rather “human behaviour”.
Once a distinction is made between human nature (biological, and which can hardly have changed since homo sapiens evolved) and socially and culturally determined human behaviour (which has changed throughout pre-history and history), then the issue becomes clearer. It can be seen, not to be about whether or not there is such a thing as biological nature which is inherited and determined by genes ( so there's “no denial of human nature” as we have stated ), but about the extent of this and in particular whether or not it includes specific ideas or behaviour patterns. It is not our consciousness that determines our social existence but our social existence which determines our consciousness. Nobody, for example, is born a racist or a patriot or a bigot - this has to be learned.
Socialism does not require us all to become altruists, putting the interests of others above our own. In fact, socialism doesn't require people to be any more altruistic than they are today. We will still be concerned primarily with ourselves, with satisfying our needs, our need to be well considered by others as well as our material and sexual needs. No doubt too, we will want to “possess” personal belongings such as our clothes and other things of personal use and to feel secure in our physical occupation of the house or flat we live in, but this will be just that – our home and not a financial asset. Such “selfish” behaviour will still exist in socialism but the acquisitiveness encouraged by capitalism will no longer exist. The coming of socialism will not require great changes in the way we behave, essentially only the accentuation of some of the behaviours which people exhibit today (friendliness, helpfulness, co-operation) at the expense of others that capitalism encourages.
Socialism is a society where would all be considered of equal worth and be able to have an equal say in the way things are run and in which we recognise ourselves as members of an interdependent community where different people perform different functions and where everybody, irrespective of their function, has access to what they need to live and enjoy life just because they are members of the human race. And this doesn't require us to be any less selfish or more altruistic than we are today – it's not about changing human nature but about changing the basis of society. We don't need to change human nature; it is only human behaviour that needs to change. Humans' behaviour has been determined by the sort of society they live in and has varied with this while their biological make-up has remained unchanged. While our genes can't be ignored, they only intervene in our behaviours in an indirect way, by programming the development of our brains.
Therefore, to understand the complexities of our behaviour, it is to our brains, not directly to our genes, that we have to look. When we do this we find that our brains allow us, as a species, to adopt – and, as prehistory and history bear out, we have in fact adopted – a great variety of different behaviours depending on the natural, economic and social environments we have found ourselves in.
So, "human nature" is not a barrier to socialism. On the contrary, our biologically evolved and inherited human capacity will allow us to live in a socialist society.