This is a difficult one to write about, because as I initially added in my tweets, “The causality of that is complex though, and not easily generalised.” But it remains true, that some who start off as Evangelicals end up ex-Evangelicals.
Firstly, correlation isn’t causation, and in the cases in which this occurs, every individual case is going to be a mass of factors. I don’t think you can blame “Patristics” for this, unless you are an apologist for other traditions (which I do hear from time to time, from RC and EO apologists who think “oh, good, you’re studying Patristics – you’ll realise the error of your Protestant Heresy and come back to the true Church”).
Nonetheless, for some individuals it probably is a contributory factor. And yet, even so this has a complexity to it. Studying Patristics opens a researcher up to a whole new theological field that is only dimly glimpsed for more evangelicals, even evangelical academics. To really enter into it as an historical theologian, and not a pirate marauder there to carry off translated one-liners for their systematic theology, requires a genuine attempt to deal with patristic authors on their own terms.
That demands, I would say, a broad ecumenical spirit. Not a suspension of one’s own convictions, necessarily, but a determination to treat with the past “in good faith”. And some, no doubt, come to view Protestantism as a deviation from the Early Church, and begin to find RC and EO arguments for their position persuasive.
Others, I suspect, are pushed in that direction – as they explore different “vistas” so to speak, they find themselves more and more estranged from the evangelical safe-playgrounds (which is not helped at all by the marginalisation of patristics in evangelicalism – they may indeed be pushed away because they are doing patristics), and more and more welcomed by other traditions (the pull of RC and EO, which says, “yes, we have a home for you”).
In one sense, I want to say, it’s not possible to be an evangelical and patristics researcher and remain unchanged in your evangelicalism, and that’s a good thing. If evangelical Protestantism is ever going to be more than just the rebellious teenage child of 15th century Medieval Catholicism, refracted through its short and revivalist history (and it ought to be more than both these things), it can and must have a claim, for its own sake, on Early Christian History. Otherwise evangelicalism really is a religion of but recent invention. And that past, if we truly think early theologians are genuine Christians, should shape our beliefs. Not just our patristic scholars though!
So, yes, some Evangelicals who head down the patristics path end up not-evangelical. That’s a complex problem, but part of the solution ought to be that evangelicalism doesn’t push them away, and out, ever so subtly, simply because patristics.