~ Updated and Revised: March 8th, 2019 ~

Benjamin Breckinridge Warfield (1851—1921) was a professor of theology at Princeton Theological Seminary (and successor of Charles Hodge and his son A. A. Hodge), and B. B. Warfield is among the greatest and most influential Reformed theologians in American history. B. B. Warfield is most well known for his defense of Biblical Inerrancy in his book The Inspiration and Authority of Bible (1915), and his defense of cessationism in his book Counterfeit Miracles (1918). B. B. Warfield wrote many essays on theological loci that have been compiled into The Works of Benjamin B. Warfield (10 Volume Set) and others. 

B. B. Warfield was not opposed to evolution or the other sciences like the other 19-20th century Reformed theologians of his day (including Charles Hodge) and they believed that science (including evolution) affirmed the Christian faith. Warfield was also an expert on John Calvin and Calvinism. 

In a fascinating essay titled "Calvin's Doctrine of Creation" (1915) made a famous statement that John Calvin's doctrine of creation was an evolutionary one!  It's a shocking statement consider that even in 2019, Calvinist evangelicals are still making bombastic statements that Evolutionary science is not compatible with the Christian faith. Warfield was not the first or only theologian to make this statement, because Charles Hodge had already affirmed evolution, and Herman Bavinck (1854-1921) made a similar statement in his 1909 stone lectures in regards to evolution science and John Calvin.

In this essay "Calvin's Doctrine of Creation", B. B. Warfield explicitly states that "Calvin's doctrine of creation is [...] an evolutionary one." Warfield explains that John Calvin lived long before Charles Darwin, so he was not aware of Darwinism or of contemporary evolutionary models, so it would be anachronistic to assert that Calvin affirm evolution as it is understood today. Calvin's doctrine of creation had features that were incorrect such as occurring over six day period, opposed to long ages. So it would be wrong to impose those antiquated features into theological speak today (in the same way it would be wrong to reject Copernicus like Calvin did.) Warfield argues that Calvin's doctrine of creation included immediate creation and mediate creation. Immediate creation was world-stuff created out of nothing (ex nihilo), but other world-stuff was later created mediate creation, which means by modification of this initial world stuff. Warfield argues that Calvin's doctrine of creation anticipates evolution, and is best described as an evolutionary theory. 

I've included a quotation from B. B. Warfield's essay "Calvin's Doctrine of Creation". This essay, and Warfield's other writings on evolution have been compiled into an excellent resource B. B. Warfield: Evolution, Science, and Scripture: Selected Writings edited by Mark A. Noll and David N. Livingstone. 

If evolutionary science is not compatible with the Christian faith (as some famous Calvinist evangelicals have said recently), then so is John Calvin, and the great Calvinist theologians Charles Hodge, B. B. Warfield, and Herman Bavinck are outside of the Christian faith too.

"It should scarcely be passed without remark that Calvin's doctrine of creation is, if we have understood it aright, for all except the souls of men, an evolutionary one. The "indigested mass," including the "promise and potency" of all that was yet to be, was called into being by the simple fiat of God. But all that has come into being since - except the souls of men alone - has arisen as a modification of this original world-stuff by means of the interaction of its intrinsic forces. Not these forces apart from God, of course: Calvin is a high theist, that is, supernaturalist, in his ontology of the universe and in his conception of the whole movement of the universe. To him God is the prima causa omnium and that not merely in the sense that all things ultimately - in the world-stuff - owe their existence to God; but in the sense that all the modifications of the world-stuff have taken place under the directly upholding and governing hand of God, and find their account ultimately in His will. But they find their account proximately in "second causes"; and this is not only evolutionism but pure evolutionism. What account we give of these second causes is a matter of ontology; how we account for their existence, their persistence, their action - the relation we conceive them to stand in to God, the upholder and director as well as creator of them. Calvin's ontology of second causes was, briefly stated, a very pure and complete doctrine of concursus, by virtue of which he ascribed all that comes to pass to God's purpose and directive government. But that does not concern us here.

What concerns us here is that he ascribed the entire series of modifications by which the primal "indigested mass," called "heaven and earth," has passed into the form of the ordered world which we see, including the origination of all forms of life, vegetable and animal alike, inclusive doubtless of the bodily form of man, to second causes as their proximate account. And this, we say, is a very pure evolutionary scheme. He does not discuss, of course, the factors of the evolutionary process, nor does he attempt to trace the course of the evolutionary advance, nor even expound the nature of the secondary causes by which it was wrought. It is enough for him to say that God said, "Let the waters bring forth. . . . Let the earth bring forth," and they brought forth. Of the interaction of forces by which the actual production of forms was accomplished, he had doubtless no conception: he certainly ventures no assertions in this field. How he pictured the process in his imagination (if he pictured it in his imagination) we do not know. But these are subordinate matters. Calvin doubtless had no theory whatever of evolution; but he teaches a doctrine of evolution. He has no object in so teaching except to preserve to the creative act, properly so called, its purity as an immediate production out of nothing. All that is not immediately produced out of nothing is therefore not created - but evolved. Accordingly his doctrine of evolution is entirely unfruitful. The whole process takes place in the limits of six natural days. That the doctrine should be of use as an explanation of the mode of production of the ordered world, it was requisite that these six days should be lengthened out into six periods - six ages of the growth of the world. Had that been done Calvin would have been a precursor of the modern evolutionary theorists. As it is, he only forms a point of departure for them to this extent - that he teaches, as they teach, the modification of the original world-stuff into the varied forms which constitute the ordered world, by the instrumentality of second causes - or as a modern would put it, of its intrinsic forces. This is his account of the origin of the entire lower creation. (See Note 45.)"

Note #45. H. Bavinck in the first of his Stone Lectures ("The Philosophy of Revelation," 1909, pp. 9-10) remarks: "The idea of development is not a production of modern times. It was already familiar to Greek philosophy. More particularly Aristotle raised it to the rank of the leading principle of his entire system by his significant distinction between potentia and actus. . . . This idea of development aroused no objection whatever in Christian theology and philosophy. On the contrary, it received extension and enrichment by being linked with the principle of theism." Calvin accordingly very naturally thought along the lines of a theistic evolutionism. 

B.B. Warfield, "Calvin's Doctrine of Creation", 
http://www.monergism.com/thethreshold/sdg/warfield/warfield_calvincreation.html