Aristotle gives four such reasons that can be applied to both his times and our own. We quote from economic historian Odd Langholm who summarizes these four reasons:
First, if property is commonly owned, “complaints are bound to arise between those who enjoy or take much but work little and those who take less but work more.” Secondly, private property will be taken better care of “because each will apply himself to it as to private business of his own.” Thirdly, to know that a thing is one’s own is pleasurable. Fourthly, the exercise of liberality requires private property.1
These reasons come from human nature and are valid for all times and peoples. It is all so simple and yet so true…
1 Odd Langholm, Economics in the Medieval Schools: Wealth, Exchange, Value, Money and Usury According to the Paris Theological Tradition 1200-1350, (Leiden: E.J. Brill), 1992, p. 172.