Mater et Magistra §213

²¹³ The attempt to find a solution to this problem has given birth to a number of theories. Some of these were little more than ephemeral; others have undergone, and are still undergoing, substantial change; others again are proving themselves less and less attractive to modern man. Why is this? It is because these ideologies do not take account of the whole man, nor even of his most important part. In particular, they take little account of certain inevitable human weaknesses such as sickness and suffering, weaknesses which even the most advanced economic and social systems cannot completely eliminate. Finally, they fail to take account of that deep-rooted sense of religion which exists in all men everywhere, and which nothing, neither violence nor cunning, can eradicate.