state is to secure those general (collective) conditions for the reproduction and maintenance of society that individuals and private enterprise cannot secure by themselves for one reason or another (e.g., because they transcend competing interests, because they are too costly for private agencies, because it is technically not possible to privatize them, or because they are not sufficiently profitable or too risky). Ecologists would nowadays probably add as a "reproduction condition" good stewardship for the physical environment. Sustainable development cannot occur if the natural environment is constantly depleted without being restored. The recycling of wastes and waste materials can be considered as a necessary and integral part of society's reproduction process. Each of these six features is the subject of much political controversy in society. Many different opinions exist about their relative importance and their effects on each other. Economists and businesspeople are often primarily concerned with the economic effects, but other intellectuals and workers are often more concerned with the non-economic effects for the health, security, and well-being of citizens. Thus, governments usually have both economic policies and social policies, population policies, environmental policies, and so on. Economic reproduction in capitalism According to Marx, in a capitalist society, economic reproduction is conditional on capital accumulation. If workers fail to produce more capital, economic reproduction begins to break down. Therefore, economic reproduction in capitalist society is necessarily expanded reproduction and requires market growth. Capital must grow, otherwise the whole process breaks down. Thus, economic growth is not simply desirable but also necessary in capitalism, not just because of population growth, but for commercial reasons. In this light, the ecological vision of a "zero-growth society" appears rather utopian; or, at the very least, its achievement would require the abolition of capitalism. Some would argue that population growth makes economic growth absolutely necessary. Others argue that population growth must be restricted with birth control methods because otherwise there will be too many people for the available resources. The real argument, though, is not about growth or the lack thereof, but rather about the kind of growth that is best for the (enlarged) reproduction of the human species as such. Ecologists may validly argue that some types of growth undermine important conditions for human survival in the longer term without invalidating other kinds of growth that are beneficial. However, there is much dispute about which kinds of economic growth are beneficial or harmful.