For context, see the previous post.
As far as I know, the mainstream of Calvinism has never asserted that God is the direct efficient cause of everything. Some hyper-Calvinists may have asserted this, but I don’t think you’ll find it in any of the major confessional statements or systematic theologies. God is always understood as working both directly (as in the initial creation, or in miracles) and indirectly (through natural law and men’s actions as proximate causes and instruments). God is understood to be the ultimate cause of everything, the first mover, which I believe was also Thomas’s position. God’s working mediately through proximate causes is often called secondary causation.
Calvin
I’m quoting the older Beveridge translation, since it is in the public domain and can easily be searched and copy-n-pasted. Pardon my laziness. I encourage you to consult the McNeill/Battles edition instead if you have it.
In the Beveridge translation, the term sometimes used for second causes is ‘inferior causes’. Calvin doesn’t talk about secondary causation as much as I had hoped; he seems more at pains to refute certain views, in which second causes don’t play much of a role. Nonetheless, he clearly affirms that God works through second causes as well as apart from them.
Institutes 1.17.1 (Use to be Made of the Doctrine of Providence):
And it is to be observed, first, that the Providence of God is to be considered with reference both to the past and the future; and, secondly, that in overruling all things, it works at one time with means, at another without means, and at another against means.
Institutes 1.17.6:
The Christian, then, being most fully persuaded, that all things come to pass by the dispensation of God, and that nothing happens fortuitously, will always direct his eye to him as the principal cause of events, at the same time paying due regard to inferior causes in their own place.
Institutes 1.17.9:
At the same time, the Christian will not overlook inferior causes. For, while he regards those by whom he is benefited as ministers of the divine goodness, he will not, therefore, pass them by, as if their kindness deserved no gratitude, but feeling sincerely obliged to them, will willingly confess the obligation, and endeavour, according to his ability, to return it. In fine, in the blessings which he receives, he will revere and extol God as the principal author, but will also honour men as his ministers, and perceive, as is the truth, that by the will of God he is under obligation to those, by whose hand God has been pleased to show him kindness. … Regarding all the aids which the creatures can lend him, as hands offered him by the Lord, he will avail himself of them as the legitimate instruments of Divine Providence.
Westminster Confession of Faith
The Westminster Confession of Faith is the chief confessional standard for presbyterianism that traces its roots back to roots in the British Isles. Together with the Westminster Larger and Shorter Catechisms, it is the confessional standard for the denomination to which I belong (the Presbyterian Church in America).
Chapter V (Of Providence):
I. God the great Creator of all things doth uphold, direct, dispose, and govern all creatures, actions, and things, from the greatest even to the least, by His most wise and holy providence, according to His infallible fore-knowledge, and the free and immutable counsel of His own will, to the praise of the glory of His wisdom, power, justice, goodness, and mercy.
II. Although, in relation to the fore-knowledge and decree of God, the first Cause, all things come to pass immutably, and infallibly; yet, by the same providence, He ordereth them to fall out, according to the nature of second causes, either necessarily, freely, or contingently.
III. God, in His ordinary providence, maketh use of means, yet is free to work without, above, and against, them, at His pleasure.
Charles Hodge
Charles Hodge was one of the most important American theologians of the 19th century. He is perhaps somewhat out of favor in the American reformed scene these days because his epistemology and apologetic method are at odds with Van Tillian presuppositionalism, which is now the prevailing view. On questions of providence, though, his views are mainstream. His Systematic Theology in many places speaks affirmatively of 'second causes’. It’s clear that he takes the Westminster view of secondary causation for granted. Here are three examples.
Systematic Theology I.I.X.2
§ 2. Mediate and Immediate Creation.
But while it has ever been the doctrine of the Church that God created the universe out of nothing by the word of his power, which creation was instantaneous and immediate, i.e., without the intervention of any second causes; yet it has generally been admitted that this is to be understood only of the original call of matter into existence. Theologians have, therefore, distinguished between a first and second, or immediate and mediate creation. The one was instantaneous, the other gradual; the one precludes the idea of any preëxisting substance, and of cooperation, the other admits and implies both. There is evident ground for this distinction in the Mosaic account of the creation. … There is, therefore, according to the Scriptures, not only an immediate, instantaneous creation ex nihilo by the simple word of God, but a mediate, progressive creation; the power of God working in union with second causes.
Systematic Theology I.I.XI.
§ 1. Preservation.
…
Creation and preservation differ, first, as the former is the calling into existence what before did not exist; and the latter is continuing, or causing to continue what already has a being; and secondly, in creation there is and can be no coöperation, but in preservation there is a concursus of the first, with second causes.
Systematic Theology I.I.XI.
§ 4. Principles involved in the Scriptural Doctrine of Providence.
…
Conclusion
Such are the general principles involved in this most difficult doctrine of Divine Providence. We should be equally on our guard against the extreme which merges all efficiency in God, and which, in denying all second causes, destroys human liberty and responsibility, and makes God not only the author of sin, but in reality the only Being in the universe; and the opposite extreme which banishes God from the world which He has made, and which, by denying that He governs all his creatures and all their actions, destroys the foundation of all religion, and dries up the fountains of piety.
I would be very curious to see how Dr. Hart would characterize the differences between Augustine’s view of God’s sovereignty and Calvin’s.