The 2nd objection is this: Supralapsarianism makes God the author of sin.
2 Having pointed out that the first objection is unfair, we must further point out that the 2nd objection is even worse. You’ll remember that this objection claims that Supralapsarianism makes God the author of sin. This is absolutely untrue! Truth be told, Infralapsarianism does not escape this false accusation either. If what Infralapsarianism teaches is correct, namely that God is free from eternity to create or not to create, and that he created knowing with infallible certainty (decreeing that man should fall), then God should not have created. Thus we see that the Infralapsarians do not escape the reproach of those who want to say that God is the cause of perdition of man and the author of sin. Again, if it’s good enough for the goose, it should be good enough for the gander. No Infralapsarian has any business lodging this objection against Supralapsarianism because that knife cuts both ways.
Let me use a critic’s own words to show that Infralapsarianism is not off the hook with regard of the question of the origin of evil. Louis Berkhof, describing Supralapsarianism, which he at least mildly disagrees with, writes, “The order of the decrees, as accepted by the Supralapsarians, is regarded as the more ideal, the more logical and unified of the two. It clearly exhibits the rational order which exists between the ultimate end and the intermediate means. Therefore the Supralapsarians can, while the infralapsarians cannot, give a specific answer to the question why God decreed to create the world and to permit the fall. They do full justice to the sovereignty of God and refrain from all futile attempts to justify God in the sight of men, while the infralapsarian hesitate, attempt to prove the justice of God’s procedure, and yet in end must come to the same conclusion as the Supralapsarians, namely, that, in the last analysis, the decree to permit the fall finds its explanation only in the sovereign good pleasure of God” (Systematic Theology, p. 121).
That statement, taken at face value, would seem to make Infralapsarianism absolutely untenable. A couple of pages later, Berkhof makes the case for Infralapsarianism even worse, when he says, “Infralapsarianism really wants to explain reprobation as an act of God’s justice. It is inclined to deny either explicitly or implicitly that it as an act of mere good pleasure of God. This really makes the decree of reprobation a conditional decree and leads into the Arminian fold. But infralapsarians on the whole do not want to teach a conditional decree, and express themselves guardedly on this matter. Some of them admit that it is a mistake to consider reprobation purely as an act of divine justice. And this is perfectly correct. Sin is not the ultimate cause of reprobation any more then faith and good works are the cause of election, for all men are by nature dead in sin and trespasses. When confronted with the problem of reprobation, infralapsarians, too, can find the answer only in the good pleasure of God. Their language may sound more tender than that of the Supralapsarians, but is also more apt to be misunderstood, and after all proves to convey the same idea” (ibid. P. 124). If you were trying to come up with a stronger defense of Supralapsarianism, you would be hard-pressed to do better than this.
As I said, Infralapsarianism is not off the hook with regard to the question of the origin of evil are sin. Sometimes people smuggle in the standard of justice that rejects God’s absolute sovereignty in order to evaluate God’s decrees by it. Berkhof complains that Supralapsarianism does not give a solution to the problem of sin. He says that it what effect dare to say that God decreed to bring it into the world by his own direct efficiency. He seems to be unaware of the fact that some theologians do dare to say that God decreed to bring it into the world by some direct efficiency. And the truth of the matter is, Infralapsarianism cannot escape this charge either. Waffling on this question frequently forces people into a position which sounds an awful lot like dualism. I understand the reticence of pinning the responsibility for the existence of evil on God in any way, shape, or form. But the "mere permission" response comes awful close to saying that some other power has the ability to generate and control sin by its own direct efficiency, which, as I said, sounds suspiciously like dualism. Pushing the responsibility onto the shoulders of men or demons, doesn’t really answer anything. Adding more cars to train does not account for its movement; for that you need an engine.