Gaudium et spes / 'Joys and hopes'Rome 1965; in Renewing the earth: Catholic documents on peace, justice and liberation,
edited by David J. O'Brien and Thomas A. Shannon (Image: NY 1977)

19. The forms and roots of atheism
... Still, many of our contemporaries have never recognized this intimate and vital link with God, or have explicitly rejected it. Thus atheism must be accounted among the most serious problems of this age, and is deserving of closer examination.
The word atheism is applied to phenomena which are quite distinct from one another. ...
Moreover, atheism results not rarely from a violent protest against the evil in this world, or from the absolute character with which certain human values are unduly invested, and which thereby already accords them the stature of God. Modern civilization itself often complicates the approach to God, not for any essential reason, but because it is excessively engrossed in earthly affairs.
193-194

20. Systematic atheism
Modern atheism often takes on a systematic expression, which, in addition to other arguments against God, stretches the desire for human independence to such a point that it finds difficulties with any kind of dependence on God. ...
Not to be overlooked among the forms of modern atheism is that which anticipates the liberation of man especially through his economic and social emancipation. ...
194-195

21. The Church's attitude toward atheism
... Still, she [the Church] strives to detect in the atheistic mind the hidden causes for the denial of God.
195
The remedy which must be applied to atheism, however, is to be sought in a proper presentation of the Church's teaching as well as in the integral life of the Church and her members.
196
While rejecting atheism, root and branch, the Church sincerely professes that all men, believers and unbelievers alike, ought to work for the rightful betterment of this world in which all alike live. ...
She [the Church] courteously invites atheists to examine the gospel of Christ with an open mind.
196