Remember George Smeaton? One of his colleagues in the Free Church College was James Buchanan (1804-1870), Professor of Systematic Theology. Buchanan published various works, one of the most useful being the one simply titled The Doctrine of Justification.
Buchanan fully subscribed to the doctrine of the counter-imputation of sin and righteousness – that just as Adam’s disobedience brought condemnation on those who he represented, so Christ’s obedience is the (only) basis of the justification of those who he represents.
Perhaps one of the oddest objections to this doctrine, and one the most easily and persistently thrown into the discussion, is that this counter-imputation is no more than a legal fiction. Buchanan went so far as to call this objection offensive, and rebuts it in one section of his exposition in a most firm and patient way.
“The imputation of sin and righteousness is not ‘a legal fiction’, if by that expression be meant anything that is unreal or untrue.
Suppose that it were justly described as a ‘legal fiction’, it might still represent an important truth, under the scheme of God’s moral government. [The consequences of the arrangement of the covenant with Adam], so far from being mere ‘legal fictions’, are assuredly very solemn realities:– the curse pronounced on the ground — the doom of universal death — the loss of God’s image — the forfeiture of his favour — the depravity of human nature — and all the evils and sufferings which have followed in the train of sin — all these are brought upon us under the operation of that law, and every one of them is as real as it is dreadful.
In like manner, … he has promulgated a scheme of redeeming mercy, and this too in a covenant form, through the second Adam as the representative of his people — imposing on him the fulfilment of its conditions, and securing to them the benefits of his work on their behalf … [The consequences of this arrangement], so far from being mere ‘legal fictions’, are substantial blessings of the highest and most permanent kind:– the pardon of sin — the restoration of God’s favour — the renewal of his image — the assurance of his love — the privilege of adoption — and the gift of eternal life – all these are brought upon us under the operation of that scheme, and every one of them is as real as it is desirable.
When we are brought face to face with such realities as these, it is vain to talk of ‘legal fictions’, whether under the law or under the gospel; for while condemnation, on the one hand, and justification, on the other, are strictly forensic or judicial acts, and must necessarily have some relation to the law and justice of God — and while the representative character both of the first and second Adam, and the consequent imputation of their guilt and righteousness to those whom they respectively represented, can only be ascribed to the sovereign will and appointment of God — yet the results are in their own nature real and true, and not, in any sense, fictitious or imaginary.
… Nothing is more remarkable in the doctrines of Christianity than this, that every one of them is simply the statement of a fact, and that they all relate either to substantive beings – God, angels, and men – or to real events, past, present, or future. … What is the doctrine of the trinity but the statement of a fact respecting the existence of distinct hypostases in his one undivided Godhead? … What is the doctrine of imputation, whether of sin or of righteousness, but the statement of a fact respecting the relation in which we stand to the first and second Adam, and the consequences which result to us from the disobedience of the one, and the obedience of the other?”
(Buchanan, Justification, BOT, p334ff)