The doctrine of predestination has undergone substantial renovation and development over time. Augustine and Thomas considered election and reprobation as two separate dogmas, where the active election of men from the mass of perdition was a distinctive act that is separate from the act of reprobation, such that it only described the grace of god in the saving of individuals. God's election of individuals did not automatically include the condemnation of the reprobates (i.e. non-elect), and this is commonly called Single Predestination. Single Predestination indicates that God does not predestine people to life in the same way or act as he predestines people to perdition.
The Reformers, most notably John Calvin and Martin Luther, replaced the doctrine of Single Predestination with a doctrine of Double Predestination, in which election and reprobation were unified in decree of predestination, therefore Double Predestination not only teaches that god predestined people to life, but in the same decree, all reprobates (i.e. non-elect) are predestined to perdition. The doctrine of predestination was no longer a message of good news to all, but good news only to the elect and horrible and dreadful news to the reprobates. John Calvin confessed that Double Predestination a horrible and dreadful decree, and that it is! Although Calvin, did not like the truth of Double Predestination, he believed it was the revealed word of God and that we should not shrink back from it in the way later reformers did by masking it in "mystery". He believed that what has been revealed, should not be hidden from anyone. Many have recoiled from this Horrible Decree like Calvin in attempts to deny it like the Arminian Reformers. However, the Arminians have also fallen in the same two fold Double Predestination by qualifying it upon an individual's free will foreseen by God, yet the two fold outcome of Double Predestination still stands firmly in their formulations -- providing no solution to horrors of the decree of reprobation.
In Karl Barth's Doctrine of Election in Church Dogmatics Vol. II/2, this history is retold and assessed in a beautiful small print section. I've reproduced the section below because his introduction shows in detail the development of the Doctrine of Predestination, and does so with a charitable assessment of John Calvin's work. Karl Barth's Doctrine of Election is contained within the later sections of Church Dogmatics II/2, and this quotation only provides a prolegomena to his solution not covered here. Barth affirms Calvin's effort to proclaim predestination as goodnews, but believed Calvin had fallen into speculation that resulted in the Dystopian Gospel of Double Predestination. Barth believes that if Calvin had stayed closer to the biblical text, especially in the Double Predestination of the man Jesus Christ (Ephesians 1:4), then the horrors of Double Predestination would have been avoided.
The Gospel is Good News, and Karl Barth is correct in identifying God's election as the Gospel, such that predestination is a message of Good News. it was the older Reformers who followed Calvin that balanced Double Predestination into a dreadful message of condemnation to half or potentially the majority of the world who did not believe! The Good News of the Gospel became a message of Horror and Dread to the mass of perdition! We must retreat from this Dystopian Gospel and shutter in horror at its message.
(The following is a direct quotation of Karl Barth's Church Dogmatics Vol. II/2 with a few modifications to the text from the T&T Clark study edition, by replacing the original Greek and Latin quotations with the corresponding italicized English Translations from the footnotes. I've also added the bold-italicized headers and broken up longer paragraphs for readability.)
Development of Single Predestination:
Augustine himself did receive here a salutary check, as is shown by the fact that on the whole he avoided reducing God's twofold dealings to one common denominator, even in concept. By predestination he always (or almost always) understood predestination to grace (a definition taken over by Peter Lombard, Sent. I, dist. 40 A) and therefore predestination to life. Predestination consists positively in election, and does not include reprobation. Thomas Aquinas held a similar concept. For him predestination was means, pre-existing in God, of the transmission of eternal life (S. th. I, qu. 23, art. I c), or, according to a later definition: a predestination from eternity for those things which are to exist, by the grace of God, in time (S. th. III, qu. 24, art. 1 c). Thomas, like Augustine, does set the two alongside: God willed among men a number whom he predestined, to be given his goodness according to the manner of his mercy by which they are spared; and a number whom he reprobated, by the manner of his justice, by which they are punished (qu. 23, art. 5 ad. 3). But more clearly than Augustine he regards reprobation as in fact a separate genus, quite apart from and standing to some extent only in the shadow of predestination. A similar view was held in the 14th century even by such strong "predestinarians" as Gregory of Rimini and John Wyclif.
Development of Double Predestination:
Already, however, Isidore of Seville in the 7th and Gottschalk in the 9th century had taught a doctrine which differed formally from that of Augustine: Predestination is twofold: either of the elect for rest, or of the reprobate for death (Isidore, sent. 2, 6, 1). Just as God has predestined all the elect to life by the free gift of his grace alone ... so he has also predestined every reprobate to the punishment of eternal death, by what is most evidently the most just judgment of his righteousness (Gottschalk, according to Hinkmar, De praed. 5). In this case predestination is an over-ruling concept, including both election and rejection. This was the usage adopted by the Reformers. In Luther's De servo arbitrio [Bondage of the Will], in Zwingli's De providentia and in the writings of Calvin, predestination means quite unequivocally double predestination: double in the sense that election and rejection are now two species within the one genus designated by the term predestination. It is true that not only in Luther but in Calvin too there are passages to dispense with this fatal parallelism of the concepts election and rejection: It is necessary to say that God, by his eternal decree, of which the cause depends on nothing else, has destined for salvation those whom he pleased, and whom -- leaving others out -- he graced with his free adoption to enlighten them by his own Spirit, that they might receive the life offered to them in Christ. But he decreed also that others should be freely unbelieving, so that destitute of the light of faith, they should remain in the darkness (De aet. Dei praed. C.R. 8, 261 f.). So, too, in the famous definition in the Institutio (III, 21, 5): We call the eternal predestination of God that decree in which he has it established in himself what he wills to become of each man. For all were not created in a like state. Rather, eternal life is foreordained for some, and eternal damnation for others. Therefore, just as each person is made for one or other of these ends, so we can say that they are predestined either for life or for death.
Balancing of Double Predestination by the post-Calvin Reformed Dogmaticians, and how Arminianism is also Double Predestination:
It was quite in the spirit of Calvin, and yet quite fatal, when many of the older Reformed dogmaticians thought that they ought to balance against the concept of the election of grace that of an election of wrath. Although they attempted to amend the doctrine, it is noteworthy that even the Arminians could not escape the concept of a "double" predestination in this sense: The predestination of God is that divine decree by which he established in the decree of his will before all temporal ages to choose those who believe in his Son Jesus Christ, to adopt them as his sons, to justify them, and if they persevere in the faith, to glorify them eternally. But he chooses to reprobate / reject, to blind and to harden those hard-hearted unbelievers, and if they persis in their hard-heartedness, to condemn them in eternity (P. a Limborch, Theo. chr., 1686, IV, 1, 5). As against that, it is one of the merits of the Canones of the Synod of Dort (1619) that a definition of predestination was there given (I, 7) which, although it did not, of course, exclude the divine reprobation, did not include or append it as an autonomous truth, being content to state positively what election is: the immutable decree of God in which, before the foundation of the world were laid, according to the most free decree of his will, out of his undiluted grace, he elected in Christ unto salvation a definite multitude of certain men (out of the whole human race which had fallen from its original wholeness into sin and death by its own fault) neither better nor more worthy than others, but laid up in the same wretched state as those others. He established Christ as the mediator from eternity, the head of all the elect, the basis of salvation, and decreed to give to him those who are to be saved, and effectually to call and bring them to communion with hi through his own Word and Spirit, to give them truth faith in him, to justify, to sanctify, and in the end to glorify those he had powerfully kept in communion with his Son, as a demonstration of his mercy and for the praise of the glorious riches of his grace. Whatever else one may think of the formula, in this form the doctrine of predestination certainly did take on again the character of evangelical proclamation which it had lost in the definitions in which it referred simultaneously and equally to grace and non-grace, salvation and reprobation.
The mistake in using "mystery" to soften the revelation of Double Predestination:
While they could not evade the importance of the content of his doctrine, some of Calvin's more timid contemporaries were much exercised about the danger of misunderstanding. They expressed the view that the doctrine of predestination out to be reserved as a kind of secret wisdom for theologians of sobriety and discretion, and not published abroad amongst the people. Calvin made the forceful answer that true discretion cannot consist in burying away a truth to which all truth servants of God testify, but only in the sober and reverent yet quiet open confession of what is learned in the school of the heavenly Teacher (De aet. Dei praed C.R. 8, 347). It would not be a true Christian simplicity, to flee from the 'harmful knowledge' of the things which God has revealed (ib., 264). What is revealed to us in Scripture is as such necessary and useful and worthy to be known by all. On no account, then, must the doctrine of predestination be withheld from believers (Instit. III, 21, 3). For just as holiness is to be preached so that God might be correctly worshiped, so also should predestination, so that those who have ears to hear may, by the grace of God, glory in God and not in themselves (De aet, Dei praed. ib., 327).
The balanced assertion of Double Predestination has changed the message of Good News (euangelion) to one of Bad News (dysangelion):
Calvin was right. But although his point was right, he could have made it more emphatically and impressively if his understanding of predestination had been less speculative and more in accordance with the biblical testimony; if it had been a strictly evangelical understanding. And with its parallel lines, with that balanced assertion of the twofold dealings of God, as a doctrine of double predestination, this is precisely what it is not. The balance gives to the doctrine neutrality which is almost scientific. It does not differentiate between the divine Yes and the divine No. It does not come down on the side of the divine Yes. On the very same level as the Yes it registers and equally definitive divine No concerning man. In such a form it is inevitable that the No should become much stronger and ultimately the exclusive note. It is inevitable that the doctrine should in the last resort be understood as bad news (dysangelion), and that as such it should be repudiated with horror (and not without inward cause).
Restoring the public presentation of Double Predestination to its positive purpose:
It is not surprising, then, that the same miserable counsel once defeated by Calvin could 150 years later be reintroduced by Samuel Werenfels as the latest wisdom--just as though nothing had happened--and that since that time it has achieved something of the dignity of an consensus view among the half-hearted. The basic demand by which any presentation of the doctrine must be measured, and to which we ourselves must also conform, is this: that (negatively) the doctrine must not speak of the divine election and rejection as though God's electing and rejecting were not quiet different, as though these divine dealings did not stand in a definite hierarchical relationship the one with the other; and that (positively) the supremacy of the one and subordination of the other must be brought out so radically that the Gospel enclosed and proclaimed even in this doctrine is introduced and revealed as the tenor of the whole, so that in some way or other the Word of the free grace of God stands out even at this point as as the dominating theme and the specific meaning of the whole utterance. It is along these lines that it will be proved whether or not the doctrine is understood in this way can it lay claim to the full publicity within in the Church rightly defended by Calvin. If not understood in this way, then even as a secret wisdom for theologians it can have no real significance, or rather it can have only a very dangerous significance.
Barth, Karl. "Church Dogmatics Study Edition 10" Ed. T. F. Torrance and G.W. Bromiley. II.2 The Doctrine of Election. Trans. G. W. Bromiley. London: T & T Clark, 2010. 15-7. Print.
Related: Augustine, Double Predestination, election, John Calvin, Karl Barth, Martin Luther, Reprobation, Single Predestination