Vickers ( Invocation and Assent: The Making and the Remaking of Trinitarian Theology ) gives a thorough and challenging account of the collapse of Trinitarian theology in seventeenth-century English Protestantism. He thinks that the collapse can be traced to three roots: The appeal to Scripture as the rule of faith; the shift in the understanding of faith from “trust” to “assent”; and the assumption about language and the necessity of “clear and intelligible” propositions. Vickers traces the formation of this paradigm in English theology from Arminius through Laud to Chillingworth and Stillingfleet and the Cambridge Platonists.

In Vickers’s telling, English Protestants not only turned from Trinitarian formulae to Scripture as the rule of faith, but changed the function of the “rule of faith.” It was possible for Scripture to function as the rule of faith, if it was seen to provide the “identifying descriptions” of the God who acted to save His people and who comes to His people in word and sacraments and prayer. In the event, though, Scripture was dismebedded from liturgy and sacraments and its function as rule of faith came to be solely an epistemic criterion of theological knowledge. Trinitarian theology was likewise dislodged from its liturgical setting to become primarily a discourse concerning the immanent Trinity.

This shift in the significance and use of the “rule of faith,” along with the other two convictions, left English Protestants vulnerable to Socinian and Unitarian attacks on the Trinity.

If Scripture is the rule of faith exclusively in the sense that it is the criterion of theological knowledge to which faith assents, and if its truths have to be stated in “clear and intelligible propositions,” then it becomes difficult to defend traditional Trinitarian dogma. It was not only Socinians who mounted the attack. Catholic apologists found the Socinian assault useful for undermining Protestant convictions concerning Scripture and tradition, and so pressed the Socinian case against Protestants.

The result was that the Trinity gradually slipped from its position of central significance in the life of the church. Instead of disclosing the name of the God who saves, along with identifying descriptions, Trinitarian formulae became simply propositions to which believers were to assent. Detached from baptism and worship, it had little practical use. Further, the fact that orthodox theologians had to expend so much space and energy to defending and explaining the Trinity proved that it failed to meet one of the basic Protestant criteria of “essential” knowledge: It was obviously not obvious, and since it wasn’t obvious it could not be understood - even if true - as a truth necessary to salvation. A certain form of Protestant sola Scriptura thus developed into a Latitudinarianism that slotted Trinitarian doctrine in a secondary position.

Protestant efforts to counter the Socinians were unsuccessful. Different proposals for explaining the “individuation” of the three Persons were attempted. William Sherlock’s Cartesian updating of the Boethian understanding of persons as an “individual substance of a rational nature” ran aground in contradictions and tilted toward tritheism, with each Person individuated as a distinct self-consciousness. John Wallis attacked Boethius, but ended up modalist. Stillingfleet tried to defend the Trinity by reintroducing the category of substance into a Lockean philosophy, but Locke himself protested effectively, and Locke’s own example showed that one could be a perfectly good English Protestant without ever taking a clear position on the Trinity.

One of the strengths of Vickers’s book is the final chapter, where he argues that, at the very time that the Trinity was on the wane among theologians, it was enjoying a hearty revival among the hymnists. An advertisement for Charles Wesley’s Hymns on the Trinity noted that “the doctrine is presented in the most intimate connection with his own spiritual interests, and those of his readers.” Trinitarian theology returned in Wesley’s hymns to where it started - back to the liturgy - awaiting a later rediscovery by the theologians.

Jehovah is but One

Eternal God and true:

The Father sent the Son,

His Spirit sent Him too,

The everlasting Spirit filled

And Jesus our Salvation sealed.

 

Senders and Sent we praise,

With equal thanks approve

The economy of grace.

The triune God of love,

And humbly prostrated before

The one thrice holy God, adored.

 

And,

The Father, Son, and Spirit dwell

By faith in all his saints below,

And then in love unspeakable

The glorious Trinity we know

Created after God to shine

Filled with the Plenitude Divine.