"The fundamental error of socialism is anthropological in nature. Socialism considers the individual person simply as an element, a molecule within the social organism, so that the good of the individual is completely subordinated to the functioning of the socio-economic mechanism.
Socialism likewise maintains that the good of the individual can be realized without reference to his free choice, to the unique and exclusive responsibility which he exercises in the face of good or evil. Man is thus reduced to a series of social relationships, and the concept of the person as the autonomous subject of moral decision disappears, the very subject whose decisions build the social order.
From this mistaken conception of the person there arise both a distortion of law, which defines the sphere of the exercise of freedom, and an opposition to private property. A person who is deprived of something he can call “his own,” and of the possibility of earning a living through his own initiative, comes to depend on the social machine and on those who control it. This makes it much more difficult for him to recognize his dignity as a person, and hinders progress towards the building up of an authentic human community."
Pope John Paul II, Encyclical Centesimus Annus − On the 100th anniversary of Pope Leo XIII’s Rerum Novarum, May 1, 1991, n. 12