Dominican friar, author of the Summa Theologiae. Synthesized Aristotelian philosophy with Christian doctrine; the reference point for later Catholic theology.
Scripture is the source of revealed doctrine, interpreted within sacred tradition and under the church's teaching office. Reason can establish much about God, but saving truth requires revelation.
Worked within the wider Latin canon, but his own treatment of the disputed books is hesitant enough that the Catholic Encyclopedia's article on the Old Testament canon names him among those whose veneration was 'tempered by some perplexity as to their exact standing.'
WORTH CORRECTINGThat Catholic Encyclopedia passage is the same one Paul Cunningham argues from in the Live Free canon episode.
Original sin is the loss of original justice. Human nature is wounded, not destroyed — it retains real capacities, and grace perfects rather than replaces nature.
Predestination is real and rests on God's will, not foreseen merit — though set within a framework of secondary causes that leaves human agency genuinely operative.
Faith is assent of the intellect to revealed truth, moved by the will. Unformed faith is real but not saving; faith formed by charity (fides formata caritate) justifies — precisely the account Luther rejected.
Justification is by grace infused into the soul, ordinarily mediated through the sacraments, genuinely transforming the person.
Christ's passion is sufficient for all and efficient for those who are joined to it — the formula both later camps would claim.
Perseverance is a gift, and no one can be certain of their own final perseverance apart from special revelation. Assurance is therefore hope rather than certainty.
Draws the sharpest technical distinction of anyone here. God is present in all things by essence, power and presence — a common mode true of every creature — but indwelling is a distinct and new mode whose only cause is sanctifying grace, ordinarily conferred through baptism. So the Spirit is genuinely everywhere and indwells only where grace is.
WORTH CORRECTINGThe q.43 material is verbatim and verified; the baptism timing is the standard sacramental account rather than a claim isolated from that article, hence established rather than researched.
"No other effect can be put down as the reason why the divine person is in the rational creature in a new mode, except sanctifying grace."Summa Theologiae I, q.43, a.3
Baptism is the sacrament of regeneration, administered to infants.
Transubstantiation: the substance of bread and wine becomes Christ's body and blood while the accidents remain. The classical articulation of the doctrine.