Mandeville lives in a transitional age in which economics, morality and politics are not clearly distinguished. He emphasises the contrast between the emerging economic rationality and Christian ethics, between utilitarianism and strict ethics. The motto 'private vices, public benefits' highlights this contradiction. The Dutch philosopher is not an economist in the modern sense, but he questions the causes of the nation's wealth and adopts some of the assumptions of mercantilism, such as the importance of a surplus balance of trade and the policy of low wages. He argues that the primary cause of a nation's wealth is wage labour and is one of the first to grasp the importance of the division of labour. He distinguishes between two types of work: wage labour, which only concerns the poor and is performed out of sheer necessity, and self-employment, which, on the other hand, allows for the satisfaction of the fundamental passions of human nature, such as the desire to improve one's condition and to be esteemed.