This article analyses the implications from modern economic theory on political philosophy. As economic growth seems the main fact of economic life, so progress of science is a key factor of economic growth in the long perspective. Scientific knowledge analyzed by economic terms appears as a kind of public good. This statement was tested against Lockeian property theory, fundamental for modern liberalism. According to Lockeian arguments, private property is a consequence of human self-ownership. If humans are the owners of their bodies, the fruits of their labor are thus legimatized property for them. Nature is indispensable in production; however we could consider them as God’s Gift. According to Locke’s theory, natural resources are the common property of all humankind, unless the people choose agriculture and animal husbandry. As we consider all natural resources to be God’s Gift, we could see them as the property of the whole human race. This indicates a claim for the egalitarian distribution of social income. This reasoning is an Old Lockeian Argument for Socialism. The New Argument is based on the assumption that scientific knowledge is the key resource used in the process of production and that knowledge is a free gift for humanity from the community of scientists. Using the terminology of economics, scientific knowledge takes the form of public good. Therefore, as science is the main factor in technological progress and economic growth, their fruits should be distributed among all people in an egalitarian mode.