“We make a distinction between de facto apostasy and de jure apostasy, between formal and material apostasy. Formal apostasy is when the church clearly and unequivocally denies an essential truth of the Christian faith. De facto apostasy is apostasy at a material or practical level, where the creeds are still intact but the church doesn’t believe the creeds anymore. The church undermines the very creeds that they say that they believe.” -R.C. Sproul, What is the Church?