47 Hence, lest concord be broken by rash charges, let this be understood by all, that the integrity of Catholic faith cannot be reconciled with opinions verging on naturalism or rationalism, the essence of which is utterly to do away with Christian institutions and to install in society the supremacy of man to the exclusion of God. Further, it is unlawful to follow one line of conduct in private life and another in public, respecting privately the authority of the Church, but publicly rejecting it; for this would amount to joining together good and evil, and to putting man in conflict with himself; whereas he ought always to be consistent, and never in the least point nor in any condition of life to swerve from Christian virtue.
Source: Immortale Dei (Vatican.va)