To soften the determinism of Calvinism, Calvinists must decrease the unflinching determinism of compatibilism. Richard Muller seeks to do so through what he calls synchronic contingency. He says synchronic contingency “means that for one moment of time, there is a true alternative for the state of affairs that actually occurs.
However, it is important to keep in mind that this alternative he puts forth is not an actually accessible alternative as is the case in libertarian moral freedom, but it is instead an alternative in potency only; to wit sufficient power to access the alternative is there if God determined that, but he did not; hence, it is not actually, in the moral moment of decision, an accessible alternative. Resultantly, unlike libertarian freedom wherein the person can choose between options and whatever option he chooses, he could have chosen differently, even with the same past, Muller’s position, like compatibilism, allows the person to choose only the option God determined for him to choose. Therefore, while it is a valiant and scholarly attempt to distance Calvinism from the micro-deterministic nature of compatibilism, it is as unsuccessful as all other Calvinistic attempts to do likewise.
Muller argues that in light of historical Reformed thought, compatibilism and libertarianism are inadequate compared to synchronic contingency to explain the relationship between divine and human causality. Muller’s argument includes significant nuances and distinctions between concepts like potency and possibility, as well as two meanings of possible.
However, in Muller’s conclusion, while God and man have the potency to more than one effect, man’s potency is not actualizable unless God wills (causes) it. He says, It also cannot be the case that God actually wills that A wills p and A actually wills not-p or that God actually wills that A actually wills not-p and A wills p. In other words, given the Reformed understanding of divine concurrence, A would not be capable of freely willing either p or not-p apart from a concurrent divine causality because apart from divine concurrence, A would not be capable of willing at all (italics added, last sentence). While he argues for multiple potencies in man, as seen here, the only one that can be actualized is the one which results from concurrent divine causality. Therefore, he is unsuccessful in reducing the micro-deterministic nature of Calvinism.
Muller’s use of potency is not what is meant by potencies within a person endowed with libertarian free will. Because in libertarian freedom, it means that the person can actually choose p or not-p since God has created him with that freedom, and whichever he did choose, he could have, given the same past, chosen differently in the moral moment of decision.
Muller’s explanation is no less dependent upon what God ultimately causes a person to choose to do at any given second than compatibilism. I do not believe he is correct in assuming that compatibilism entails animalistic instinctual or a non-human mechanical experience; nor is the human being so designed by God that he is only capable of being endowed with one potency, all of which he thinks synchronic contingency overcomes. I think he is demonstrably wrong about what compatibilism entails.
An accurate understanding of compatibilism means that, as designed by God, a human could have been given a different past (or nature) wherein he would have chosen differently; thus, he would have different potency. Further, I do not believe compatibilism entails that humans do not have an experiential sense of deliberation and choice (non-human mechanical) as he suggests, but only that it is not objective, as is the case with libertarian moral freedom. Of course, there is a subjective experiential deliberation and, had God so willed, he could have given the individual a past so that the rapist would freely desire to not rape, but the compatibly-endowed human can only choose what God determined he choose through determinative antecedents.
In this sense, according to both synchronic contingency and compatibilism, a person could have chosen differently if God would have determined (caused) him to do so but in neither case has God endowed man with freedom so that he can actually choose differently than what God did not ultimately determine (cause through various causations) him to do. Therefore, it is most difficult to glean a substantive difference in outcome from Muller’s view and compatibilism.
Although Muller rejects both compatibilism and libertarianism, he seems to seek to maintain the sovereign control and determinism of compatibilism and a semblance of otherwise choice of libertarianism, which cannot properly and compatibly exist together. Even though Muller’s highly nuanced layered approach to divine and human causality nuances compatibilism, it does not significantly distance itself from what compatibilism provides. I agree with Calvinist Paul Helm that Muller does not successfully move outside of a deterministic and compatibilist framework, and that synchronic contingency . . . provides no satisfactory explanation of human freedom and divine determination.
Linda Trinkaus Zagzebski says, The reason causal determinism takes away free will is not that it makes it the case that I cannot do otherwise, but that it makes it the case that my choices counterfactually depend on previous states of affairs. To wit, one’s past determines every choice (creation, nature, or previously determined choices). Given compatibilism, a person cannot choose differently with his same past. For him to choose differently, he would have to have a different past. Thus, in the final analysis, Muller has presented a sophisticated determinism in which the micro-determinism is no less than that of compatibilism. Consequently, Calvinism, properly understood, means that God is ultimately responsible for every good and holy act as well as every sinful and evil act of man.
(See my articles: Calvinist Paul Helm Fails to Acquit God of Causing Evil; The Word “Permit” Is As Micro-Determined AS Everything Else; D.A. Carson Fails to Absolve God of Causing Evil, and Calvinism Fails to Absolve God from Causing the Fall ).
 COMPATIBILISM: Determinism and moral responsibility are compatible, hence the name. This compatibility is not achieved by compatibilism being less deterministic than hard determinism. Rather, it is achieved by defining free choice to mean as long as a person chooses according to his greatest desire, he has made a free choice for which he is morally responsible; even though given the same past, he cannot choose differently in the moral moment of decision.
Consequently, the difference between compatibilism (soft determinism) and hard determinism is not to be found in the levels of the deterministic nature of each since they are the same. Rather, the difference is compatibilism simply contends people are morally responsible for their choices if they are made according to their greatest desire, and hard determinism says they are not. Therefore, moral responsibility is the product of defining free choice as a person acting in accordance with his greatest desire even though the desire is determined. Resultantly, it is most precise to say that compatibilism entails a determined free choice.
LIBERTARIAN: Man is not determined. He has the actual ability to choose between accessible options, at least in some scenarios. Libertarians contend determinism is not compatible with moral responsibility. Man possesses actual otherwise choice and can, therefore, act or refrain in the moral moment of decision, given the same past within a given range of options, in some scenarios.
Extensivism (non-Calvinism) argues God endowed man with this ability, which is an aspect of being created in the image of God. God determines the range of options. Adam’s range of options, the result of creative grace, was greater than mankind’s options after the fall. Fallen man can still choose between options, but the range of options is less than man had prior to the fall. This lessening includes losing the ability to make choices that are inherently righteous or spiritually restorative (making one right with God) based solely on creative grace. In order to make an inherently righteous choice or one that is spiritually restorative, God had to provision redemptive grace, grace enablements, which he did.
 Richard A. Muller, Divine Will and Human Choice: Freedom, Contingency, and Necessity in Early Modern Reformed Thought (Grand Rapids: Baker Academic, 2017), 27.
 Richard A. Muller, Divine Will and Human Choice: Freedom, Contingency, and Necessity in Early Modern Reformed Thought (Grand Rapids: Baker Academic, 2017), 27, 29, 39, 57,58.
 Richard A. Muller, Divine Will and Human Choice: Freedom, Contingency, and Necessity in Early Modern Reformed Thought (Grand Rapids: Baker Academic, 2017), 57,61.
 Richard A. Muller, Divine Will and Human Choice: Freedom, Contingency, and Necessity in Early Modern Reformed Thought (Grand Rapids: Baker Academic, 2017), 314.
 Richard A. Muller, Divine Will and Human Choice: Freedom, Contingency, and Necessity in Early Modern Reformed Thought (Grand Rapids: Baker Academic, 2017), 13, 323.
 Richard A. Muller, Divine Will and Human Choice: Freedom, Contingency, and Necessity in Early Modern Reformed Thought (Grand Rapids: Baker Academic, 2017), 61.
 Richard A. Muller, Divine Will and Human Choice: Freedom, Contingency, and Necessity in Early Modern Reformed Thought (Grand Rapids: Baker Academic, 2017), 29. See also pages 61,62. See Helm’s response to Muller, Jonathan Edwards and the Parting of the Ways?
https://jestudies.yale.edu/index.php/journal/article/view/141/98. Accessed 1/9/20. For another Calvinist who thinks Muller is unsuccessful in making a complete break from compatibilism, see Derek Rishmawy, Divine Will and Human Freedom by Richard Muller (A Review) June 25, 2017, https://derekzrishmawy.com/2017/06/25/divine-will-and-human-freedom-by-richard-muller-a-review/ , accessed 1/9/20.
 Linda Trinkaus Zagzebski, The Dilemma of Freedom and Foreknowledge (New York: Oxford University Press 1991), 161,62.