Victor Preller's Divine Science and the Science of God makes an unjustly neglected contribution to understanding the apophaticism of Thomas Aquinas and, by extension, the possibilities and constraints of theological discourse. Preller contends that, according to Thomas, God-talk can be meaningful though not intelligible. That is, by faith one can know that one's propositions refer to God; one cannot, however, know how they do so. The first part of the article explains the main inferences leading up to these conclusions. The second part attends to some key passages in Thomas' Summa Theologiae in order to substantiate Preller's interpretation. Spelling out these passages requires coming to grips with Aquinas’ distinction between the ‘thing signified’ (res significata) and ‘mode of signification’ (modus significandi). Armed with this second stock of concepts, the argument doubles back on the conclusions already set out: building on Preller, I argue that Thomas distinguishes between meaning and intelligibility for semantic reasons, judgements about the practice of language which are bound up with certain other ontological judgements. Throughout the article, the virtues of this line of interpretation are compared and contrasted with the position laid out in Kevin Hector's article, ‘Apophaticism in Thomas Aquinas: A Reformulation and Recommendation’, Scottish Journal of Theology 60/4 (2007), pp. 377–93.