Thomas Aquinas, Summa Theologiae

Objection 1: It seems that the knowledge of God is not the cause of things. For Origen says, on Rm. 8:30, "Whom He called, them He also justified," etc.: "A thing will happen not because God knows it as future; but because it is future, it is on that account known by God, before it exists."

Objection 2: Further, given the cause, the effect follows. But the knowledge of God is eternal. Therefore if the knowledge of God is the cause of things created, it seems that creatures are eternal.

Objection 3: Further, "The thing known is prior to knowledge, and is its measure," as the Philosopher says (Metaph. x). But what is posterior and measured cannot be a cause. Therefore the knowledge of God is not the cause of things.

On the contrary, Augustine says (De Trin. xv), "Not because they are, does God know all creatures spiritual and temporal, but because He knows them, therefore they are."

I answer that, The knowledge of God is the cause of things. For the knowledge of God is to all creatures what the knowledge of the artificer is to things made by his art. Now the knowledge of the artificer is the cause of the things made by his art from the fact that the artificer works by his intellect. Hence the form of the intellect must be the principle of action; as heat is the principle of heating. Nevertheless, we must observe that a natural form, being a form that remains in that to which it gives existence, denotes a principle of action according only as it has an inclination to an effect; and likewise, the intelligible form does not denote a principle of action in so far as it resides in the one who understands unless there is added to it the inclination to an effect, which inclination is through the will. For since the intelligible form has a relation to opposite things (inasmuch as the same knowledge relates to opposites), it would not produce a determinate effect unless it were determined to one thing by the appetite, as the Philosopher says (Metaph. ix). Now it is manifest that God causes things by His intellect, since His being is His act of understanding; and hence His knowledge must be the cause of things, in so far as His will is joined to it. Hence the knowledge of God as the cause of things is usually called the "knowledge of approbation."

Reply to Objection 1: Origen spoke in reference to that aspect of knowledge to which the idea of causality does not belong unless the will is joined to it, as is said above.

But when he says the reason why God foreknows some things is because they are future, this must be understood according to the cause of consequence, and not according to the cause of essence. For if things are in the future, it follows that God knows them; but not that the futurity of things is the cause why God knows them.

Reply to Objection 2: The knowledge of God is the cause of things according as things are in His knowledge. Now that things should be eternal was not in the knowledge of God; hence although the knowledge of God is eternal, it does not follow that creatures are eternal.

Reply to Objection 3: Natural things are midway between the knowledge of God and our knowledge: for we receive knowledge from natural things, of which God is the cause by His knowledge. Hence, as the natural objects of knowledge are prior to our knowledge, and are its measure, so, the knowledge of God is prior to natural things, and is the measure of them; as, for instance, a house is midway between the knowledge of the builder who made it, and the knowledge of the one who gathers his knowledge of the house from the house already built.

Articulus 8

Argumentum 1

Ad octavum sic proceditur. Videtur quod scientia dei non sit causa rerum.

Dicit enim Origenes, super epistolam ad Rom., non propterea aliquid erit, quia id scit deus futurum; sed quia futurum est, ideo scitur a deo antequam fiat.

Argumentum 2

Praeterea, posita causa ponitur effectus. Sed scientia dei est aeterna. Si ergo scientia dei est causa rerum creatarum, videtur quod creaturae sint ab aeterno.

Argumentum 3

Praeterea, scibile est prius scientia, et mensura eius, ut dicitur in X metaphys..

Sed id quod est posterius et mensuratum, non potest esse causa.

Ergo scientia dei non est causa rerum.

Sed Contra

Sed contra est quod dicit Augustinus, XV de Trin., universas creaturas, et spirituales et corporales, non quia sunt, ideo novit deus; sed ideo sunt, quia novit.

Corpus

Respondeo dicendum quod scientia dei est causa rerum. Sic enim scientia dei se habet ad omnes res creatas, sicut scientia artificis se habet ad artificiata. Scientia autem artificis est causa artificiatorum, eo quod artifex operatur per suum intellectum, unde oportet quod forma intellectus sit principium operationis, sicut calor est principium calefactionis. Sed considerandum est quod forma naturalis, inquantum est forma manens in eo cui dat esse, non nominat principium actionis; sed secundum quod habet inclinationem ad effectum. Et similiter forma intelligibilis non nominat principium actionis secundum quod est tantum in intelligente, nisi adiungatur ei inclinatio ad effectum, quae est per voluntatem. Cum enim forma intelligibilis ad opposita se habeat (cum sit eadem scientia oppositorum), non produceret determinatum effectum, nisi determinaretur ad unum per appetitum, ut dicitur in IX metaphys..

Manifestum est autem quod deus per intellectum suum causat res, cum suum esse sit suum intelligere.

Unde necesse est quod sua scientia sit causa rerum, secundum quod habet voluntatem coniunctam. Unde scientia dei, secundum quod est causa rerum, consuevit nominari scientia approbationis.

Ad 1

Ad primum ergo dicendum quod Origenes locutus est attendens rationem scientiae, cui non competit ratio causalitatis, nisi adiuncta voluntate, ut dictum est.

Sed quod dicit ideo praescire deum aliqua, quia sunt futura, intelligendum est secundum causam consequentiae, non secundum causam essendi. Sequitur enim, si aliqua sunt futura, quod deus ea praescierit, non tamen res futurae sunt causa quod deus sciat.

Ad 2

Ad secundum dicendum quod scientia dei est causa rerum, secundum quod res sunt in scientia. Non fuit autem in scientia dei, quod res essent ab aeterno. Unde, quamvis scientia dei sit aeterna, non sequitur tamen quod creaturae sint ab aeterno.

Ad 3

Ad tertium dicendum quod res naturales sunt mediae inter scientiam dei et scientiam nostram, nos enim scientiam accipimus a rebus naturalibus, quarum deus per suam scientiam causa est. Unde, sicut scibilia naturalia sunt priora quam scientia nostra, et mensura eius, ita scientia dei est prior quam res naturales, et mensura ipsarum. Sicut aliqua domus est media inter scientiam artificis qui eam fecit, et scientiam illius qui eius cognitionem ex ipsa iam facta capit.