1. Exegetically. The Scriptures nowhere speak of atonement in universal terms, where the word "universal" is supposed to convey the idea that the atonement was intended to benefit each and every man or sinner. The opposite is the case: the Scriptures of the Old and New Testaments affirm that atonement (whether ceremonial or actual) is made for the sin of a specific people, and that it effects precisely what it was intended to effect in each and every case – the covering of sin.
1 Tim. 4:10 says nothing about atonement, so it is clearly a case of theological presupposition reading atonement into the verse when one affirms it teaches an open ended view of the atonement. The verse does not even specify what is meant by the term "salvation" when it is affirmed that God is the Saviour of all men. Any theological abstraction and application of the apostle's faithful saying should not be extended so as to trespass the parameters of its original context.
John 3:16 at the most teaches what the Marrowmen would call an indefinite gift of Christ for sinners of mankind. But such an indefinite giving of Christ does not entail that each and every man is the object of the Father's gift. Reference to a class of people does not ipso facto include every member of that class. "Christ Jesus came into the world to save sinners" does not imply that He came to save every sinner, but only that the persons whom He came to save belonged to the class of people known as "sinners." Likewise, the fact that the Father gave Christ to the world of sinners indefinitely only means that the class of people to whom Christ was given in actual fact belonged to the “world;” and the most natural point of reference for understanding the term "world" is in contradistinction from the subset of people from whom Nicodemus came, who believed that salvation is of the Jews. Hence the only universalising element in John 3:16 is that of extending kingdom privileges beyond the ethnic boundaries of Judaism.
Hypothetical universalism is contrary to reformed biblical theology.
(1.) Dr. Muller's scholarly reputation grew as a result of the immense research and writing which he undertook to substantiate his hermeneutic of continuity between the original reformers and the scholastic development of their thought in later periods. Such an undertaking effectively buried the Calvin v. Calvinist idea of an earlier reformed tradition which might be regarded as existing beside the scholastic development and better representing the thought of the reformers. This being the case, one can hardly expect his scholarly work to be accepted as the basis for resurrecting the Calvin v. Calvinist hermeneutic by acknowledging Amyraldism as a legitimate trajectory of reformed thought.
(2.) One should be wary about any claim of unearthing new materials which challenge the old belief in a strictly limited atonement in the reformed tradition. Selective quotation often does not deal fairly with the source nor take into account the structure of thought within which the quoted author operated. It is very easy to read modern methods of stating the question back into past writings without taking the time to understand the way questions were asked and discussed in the period. This is simply poor historical theology.
Hypothetical universalism is contrary to reformed historical theology.
3. Dogmatically. "Hypothetical universalism" -- what is it? It is a universalism which is never realised historically. It is based on a conjecture that God's loving nature demands He desire the salvation of all men and accordingly make provision for that salvation in the death of Jesus Christ. Of course it might as easily be argued that His just nature likewise demands the damnation of all sinners without remedy. One hypothesis is just as valid as the other, being based in a preconception of the nature of God which has not been manifested by the unconditioned counsel of His own will, Eph. 1:11; and there is little doubt that in the course of all this hypothesising into the mysterious nature of God the glory of free grace is obscured. Hence it is better to simply adhere to what the Scriptures reveal to us concerning the inscrutable counsel of His own will and not pry into hypothetical secrets of what might have been should God have been pleased to decree it.
But why the hypothesis? Its advocates tell us it gives them the warrant to say to a sinner, "Jesus Christ died for you." Well suppose for a moment we were to accept this hypothesised universalism, what would it establish? Not that Jesus Christ died for each and every sinner, but that he died hypothetically or conditionally for them. It takes a great leap in logic to move from a hypothetical proposition to an absolute fact. Yet this is precisely what is done by the hypothetical universalist. He argues from a hypothetical to a real death of Christ for each and every sinner of mankind. Clearly, then, an hypothetical universalism does not warrant anyone to tell a sinner that Christ really died for him, but only that Christ died conditionally for him. This point was so persuasively argued by William Twisse against Tilenus that it is a wonder anyone would ever again venture to assert a real universalism on the basis of a hypothetical one. More wonderful still is the fact that Twisse's name has come to be enrolled on the register of reformed universalists.
Hypothetical universalism is contrary to reformed systematic theology.
4. Pastorally. What is gained on a practical level by reassuring the unrepentant sinner that God loves him, has given Jesus Christ to die for him, and now longs to impart the blessings purchased by Jesus Christ for him? Need we look any further than the spurious results obtained by such mass crusades as conducted under Arminian evangelists, who have been peddling this counterfeit gospel for decades? The result has been whole generations of unconverted sinners who live in the cursed and presumptuous assurance that Jesus is theirs, and, live as they will, their place in heaven is guaranteed by nothing less than a universal redemption. Clearly such an approach is contradictory to the apostolic counsel, which insisted that if Christ died for all, then were all dead: and that he died for all, that they which live should not henceforth live unto themselves, but unto him which died for them, and rose again, 2 Cor. 5:14, 15. Again, that those for whom Christ was crucified are crucified with Christ, and no longer live, but Christ lives in them by faith, Gal. 2:20. Such pastoral counsel demands a limited, particular reference of the atonement to actual believers only.
But we must apply this message to saints also. What does universalism do for them? Nothing less than throw the whole scheme of salvation into doubt and rob them of that assurance which belongs to them in Christ. What has become of the inspired logic of the apostle, Rom. 5:10, who argues, "For if, when we were enemies, we were reconciled to God by the death of his Son, much more, being reconciled, we shall be saved by his life?" or that of Rom. 8:34, where it is maintained that because Christ has died there is none to condemn those for whom He died? It has all become empty rhetoric; for the death of Jesus Christ, with all His saving benefits, is made hypothetical, conditional upon something the believer must do in order to complete the work.
Hypothetical universalism is contrary to reformed pastoral theology.
5. Confessionally. There is no place for a hypothetical universalism in the system of doctrine as taught by the Westminster Confession of Faith. As William Cunningham astutely observed in the 19th century, the Confession and Catechisms teach the impetration of redemption is co-extensive with the application of redemption. Larger Catechism, Question 59 asks, "Who are made partakers of redemption through Christ?" and the catechumen is taught to answer, ""Redemption is certainly applied, and effectually communicated, to all those for whom Christ has purchased it; who are in time by the Holy Ghost enabled to believe in Christ according to the gospel."
Hypothetical universalism is contrary to reformed confessional theology.