"In order to establish the moral framework that grounds the central claim of penal substitution it will be argued that (1) punishment is an appropriate response to intentional human wrongdoing and (2) it is good in some circumstances for humans to exact that punishment. We will then proceed to argue from the human context to the divine context: (3) punishment is an appropriate divine response to intentional human wrongdoing and (4) it is good in some circumstances for God to exact that punishment on wrongdoers, and (5) the goodness of such punishment can still be achieved by God's taking that punishment upon Himself in the person of Jesus Christ." - Steve L. Porter, "Dostoyesvky, Woody Allen, and the Doctrine of Penal Substitution", in Paul Copan and William Lane Craig, eds., Contending with Christianity's Critics (Broadman and Holman, 2009) 233-248: p. 238.
This is an analogical argument. Porter argues that there are key similarities between human and divine punishment; so if the former is morally plausible, then the latter is likely to be as well.
But it takes little more than a cursory reading of the quote above to notice that the human context, upon which the analogy is based, is missing a key element.
Let's accept, for the sake of argument, that, from (1) and (2), we can infer, by analogy, (3) and (4). But upon what basis do we arrive at (5)? And is not (5) the chief cause of the moral controversy about the doctrine of penal substitution?
Earlier in the piece, Porter tries to divert our attention by suggesting that the real reason why so many have rejected this doctrine is that punishment, per se, is felt, by many, to be morally unnecessary, if not repugnant.
"[There is] and increasing tendency to see an emphasis on punishment as in some sense outdated or inhumane. The common idea is that we, let alone God, have moved beyond such primitive and violent ways of dealing with our anger. . . . [This] shift in intuitions regarding punishment . . . helps to explain why there has been a recent resurgence of objectors to penal substitution." p. 234.This is a red herring. The vast majority of those who reject a penal substitutionary theory of the atonement do so because they cannot see how it could be morally acceptable for the punishment that is deserved by an offender (human sinners) to be 'taken on by' or 'transferred to' the innocent victim (God in the person of Jesus Christ). Or, as Porter puts it:
"[T]he central claim [of the doctrine of penal substitution] is that in His voluntary suffering and death, Christ takes on the penal consequences of sin on behalf of human sinners." p. 237Moreover, those who have objected to this doctrine typically do so by arguing that this transaction has no (morally defensible) analogy within the human domain. It is this key objection that Porter, in this article, seems to side-step altogether.
The problem with penal substitution is that it entails that someone can be punished even if they in no way deserve this treatment - even if they are the innocent victim of the wrongdoing in question. The doctrine breaks the moral connection between culpability and punishment. The guilt or innocence of the person being punished is beside the point.
This violates one of the most widely held moral intuitions that we have. The most serious wrong that can be committed by our criminal justice system is to punish the innocent. And it is far worse if it does so knowingly. It is precisely to honor this deeply embedded intuition that we have such elaborate and expensive court systems. This principle is part of what we mean by 'the rule of law'.
None of this is given even a passing mention by Porter. He more or less just asserts that it does not matter, from a moral point of view, who is punished. What is important about punishment is not that it is directed against the guilty. Rather, it is that the punishment must objectively re-express the value of the victim, and that the wrongdoing is seen to be taken with utter seriousness. And this expressive function, he supposes, can be achieved even if the punishment is taken on by an innocent victim.
"The goodness of the punishment is still seen in that Christ's going to the cross for our sins takes sinners and their sin with utter seriousness and objectively reexpresses the value of the God head in response to the devaluing of the Godhead expressed by human sin. By looking to the cross, we too can perceive the importance God attaches to us, to the gravity of our offense, and to the right valuing of the Godhead." p. 243.But it is not difficult to see how there could be no morally justifiable human parallel to this claim. Imagine if a judge were to sentence the innocent victim of a crime to 10 years in prison, and used the following justification in his supporting statement:
"I believe that sentencing the victim to 10 years of penal servitude takes the offender and his crime with utter seriousness and objectively reexpresses the value of the victim in response to the devaluing of their human dignity and worth expressed by the crime."The judge would, with absolute justification, be removed from the bench within seconds.
In short, so far as this article is concerned, Porter has not provided us with any reason to think that "Christ's suffering the penal consequences of human sin on behalf of sinners" is remotely plausible from a moral point of view.