Here are some striking words from Coleridge, which it is not hard to adapt to current controversies.
“Address Delivered at Bristol” from The Friend, First Section, Essay XVI
The man who would find truth, must likewise seek it with a humble and simple heart, otherwise he will be precipitate and overlook it; or he will be prejudiced, and refuse to see it. To emancipate itself from the tyranny of association, is the most arduous effort of the mind, particularly in religious and political disquisitions. The assertors of the system have associated with it the preservation of order and public virtue; the oppugners, imposture and wars and rapine. Hence, when they dispute, each trembles at the consequence of the others opinions instead of attending to his train of arguments. Of this however we may be certain, whether we be Christians or infidels, aristocrats or republicans, that our minds are in a state insusceptible of knowledge, when we feel an eagerness to detect the falsehood of an adversary’s reasoning, not a sincere wish to discover if there be truth in them;—when we examine an argument in order that we may answer it, instead of answering because we have examined it.
Our opponents are chiefly successful in confuting the theory of freedom by the practice of its advocates: from our lives they draw the most forcible arguments against our doctrines. Nor have they adopted an unfair mode of reasoning. In a science the evidence suffers neither diminution nor increase from the actions of its professors; but the comparative wisdom of political systems depends necessarily on the manners and capacities of the recipients. Why should all things be thrown into confusion to acquire that liberty which a faction of sensualists and gamblers will neither be able nor willing to preserve?
Obviously the example of the Federal Vision controversy leaps to mind. And Coleridge has some good warnings for us in this regard. If your claim is that Federal Vision doctrine (or the Truly Reformed doctrine of its vocal opponents) is scriptural, then it must also be a doctrine according to godliness. And so judging of the truth of the doctrine by the practice of its professors is not a heinous defection from the high standard of real rationality. Of course it is true that a graceless individual may say the truth, and a truthless individual be kind and polite. But if you maintain that your doctrine encompasses the Biblical teaching on salvation, assurance, growth in grace, the right use of the means of grace, and so forth, it is hardly unreasonable to request some demonstration of the beneficial effects of your right teaching: and where better to look for the fruit of that teaching than in the lives of its teachers?