Ich liebe die Serie der Cambridge Companion, den Nachschlagewerken für Autoren, wichtige Werke und Epochen aus der Geistes-/Literaturgeschichte. Zu Barth, Lewis und Calvin habe ich bereits Rezensionen geschrieben.
Zur Zeit liegen die Companion zu Kants “Kritik der reinen Vernunft” und zu von Aquins “Summa Theologiae” bei mir. Ich beginne bei den einführenden Aufsätzen und wähle mir dann weitere aus. Der Aufsatz zur Gotteslehre (“God” von Brian Davies) ist sehr zu empfehlen. Ich zitiere Auszüge zu den Erklärungen für Gottes Einfachheit (S. 89-93, Hervorhebungen von mir):
For Aquinas, the most striking difference between God and his effects (i.e., his creatures) lies in the fact that God is simple, not composite.
Here Aquinas means that certain ways in which creatures can be thought of as having parts cannot be attributed to God.
there are beings (entia) which can be distinguished into two kinds. There are entia per se – which Aquinas takes to be naturally occurring units (like people or trees). There are also entia per accidens – artificial units composed of parts with an independent existence of their own (like computers or houses), things with respect to which the parts precede the whole.
substances have distinct natures or substantial forms. But they can also possess properties or qualities which they can lose without altering what they are by nature. A cat, say, can become lighter or heavier without ceasing to be what it is by nature (i.e., a living cat). Aquinas calls these non-essential properties accidental forms, and he therefore distinguishes between substances and accidents. He also distinguishes between substantial change and accidental change. For him, something undergoes a substantial change when it ceases to exist as the kind of thing it is (as is the case with, for example, a cow that is slaughtered). An accidental change, by contrast, is a modification in something that does not prevent it from being what it is…
For Aquinas, as well as having intelligible or understandable forms, some things can have an unintelligible/non-formal factor with which we can only acquaint ourselves physically. This he calls matter, and he takes it to be the principle of individuation when it comes to things belonging to kinds. …
Now with all that behind us we can return to God and Aquinas’ claim that God is not composite. For part of this amounts to the insistence that God is (a) not something having form and matter, (b) not something capable of having accidental forms, and (c) not a substance belonging to a kind to which others can be thought of as belonging. There is no form and matter in God, says Aquinas, because God is immaterial. For Aquinas, material things are bodily things while ‘God is in no way a body’. There can, says Aquinas, be no accidental forms in God since there can be no change in God. And, holds Aquinas, God is no instance of a kind (or cannot intelligibly be thought of as such) since he is immaterial. Given that we distinguish between instances of a kind by virtue of their materiality, we cannot, Aquinas reasons, think of God as one of a kind if he is nothing material. In fact, Aquinas also wants to say, we cannot distinguish between the individual that God is and the nature that he has. …
for Aquinas it is just as true to say that, for example, God is goodness as it is to say that God is good. And, for him, this means that, though we use different predicates when speaking of God (though we say, for example, that God is powerful, wise, knowing, and so on), the predicates in question (though not synonymous considered as pieces of language) do not signify properties that are really distinct in God. For Aquinas, God just is, simply and in an undivided way, all that we truly say that he is insofar as we state what he is essentially. Aquinas thinks that all that is in God is God.