The theory of Professor Swinburne's paper is more elusive than might first appear. One formulation, in which he says he concurs with Aquinas and Scotus, is that although ‘there are necessary moral truths independent of the will of God’ there are also ‘many contingent moral truths brought about by the commands or other acts of God’. An apparently different view that he also recommends is that ‘contingent moral truths (e.g. that what you did yesterday was good) derive their truth from some contingent non-moral truth (e.g. that what you did yesterday was to feed the starving) and some necessary moral truth (e.g. that all acts of feeding the starving are good)’. My problem with reconciling these two different thoughts is that according to the second, it sounds as though God can only adjust the non-moral facts, such as whether there are starving to be fed, or whether you fed them yesterday. But according to the first, God gets in there commanding and recommending and generally throwing his moral weight around.
Consider, for instance the good old Biblical and Islamic favourite, the stoning of females who have sex outside marriage, voluntarily or not. Let us suppose that there are worlds in which this is a good thing, and worlds in which it is not: it is contingent whether it is a good thing. What might it be contingent upon? One view is that it is other straight, natural, facts of the case. Perhaps in the former worlds, stonings work to encourager les autres, and that this is a sufficient benefit to outweigh the disadvantage to the stonees. In the other worlds they do not. We can suppose that Professor Swinburne's God was responsible for this contingent difference, by making one kind of human being easier to deter than the other.
The first theory allows for a different possibility. We can now imagine the two possible worlds with every single natural, empirical, and causal, truth the same. But in one God has decided to recommend stoning, or even command it, while in the other he has not. On this theory, stoning goes up the moral ladder in one, and not in the other. This of course immediately confronts the Euthyphro problem: how is God's say-so supposed to make the difference? Is it arbitrary? Is it authoritative? How can it be, if it is indifferent to the factual identity? Professor Swinburne gives us three reasons why God might recommend or even command us to do things that are otherwise not good or still less obligatory. None of them does him, or us, much credit. The first is to encourage or frighten us into doing what we might otherwise not do, the second is to get us to be loyal to institutional arrangements that might otherwise lapse, and the third, again, is pour encourager les autres as when God ‘might command those whose marriages have much more serious problems not to get divorced, in order to encourage those with lesser problems to persist in their efforts to solve them’. So, to take my example, suppose that stoning unchaste females is pretty neutral, but that for some reason or another – perhaps a nascent sense of humanity – it is rather difficult for us to do it, or we actually prefer not to. God might step in and command or at least recommend it, in order to boss us about for our own good, or to cement some tribal or religious allegiance or other, or for some other good down the line that he has spotted but that we haven't managed to spot for ourselves. This can't be much of a good, since there is the other world where the sum of empirical and causal truths is the same, but he does not bother to command or recommend such actions. Anyhow God's gentle nudge, or rather more peremptory command, would be enough to overcome any incipient reluctance to stone females, and set the boat back on God's preferred course.
Someone might say that my example is tendentious, but historically it must be a fair example of at least the kind of case we need to think about. If we prefer a less charged example, we could stick with Professor Swinburne's own example of God selecting Sunday rather than Friday or Saturday for preferred worship, that day becoming good as a result.
Professor Swinburne realizes that the epistemology of these nudges and directives is a little tricky, and the anthropological and historical record bears him out, since at different places and times people read them so differently. He tells us how it is done:
we need a revelation well-authenticated by a divine signature in order to know what God has commanded. Such a signature would be provided by a miracle (involving a violation of natural laws which God alone can bring about) accompanying the teaching of some prophet who purports to tell what God has commanded, such as the resurrection of that prophet from the dead fulfilling and forwarding the prophet's teaching.
It is interesting that nearly three centuries after Hume this can still be the way it works. Of course, it will require a bit of pic'n'mix, since there are those confusing stories about the equivalent miracles done by the people who interpret the commands differently. Jesus thought that God did not approve of stoning, and rose from the dead to authenticate that this was his view. But the Prophet thought otherwise, and flew thousands of miles in the blink of an eye to authenticate that contrary view. And one of them, but not both, must be true, because people have said so.
Actually, in a straight contest I am not sure that the Christians win this particular battle. The historian Gibbon gently suggests the problem of the silence of those you might have expected to get bowled over, discussing certain events supposed to have happened in the Roman empire:
The lame walked, the blind saw, the sick were healed, the dead were raised, demons were expelled, and the laws of Nature were frequently suspended for the benefit of the Church. But the sages of Greece and Rome turned aside from the awful spectacle, and pursuing the ordinary occupations of life and study, appeared unconscious of any alterations in the moral or physical government of the world. Under the reign of Tiberius, the whole earth, or at least a celebrated province of the Roman empire, was involved in a preternatural darkness of three hours. Even this miraculous event, which ought to have excited the wonder, the curiosity and the devotion of mankind, passed without notice in an age of science and history …Footnote 1
But I want to end on a note of agreement. I thoroughly agree with Professor Swinburne that without relying on miracles there would not even be his little niche for God in amongst the human attitudes and institutions of morality. One can seldom treat these topics by doing better than finishing with Hume, and on this very point of the way in which natural theology is silent without the revelations that miracles afford. For the only alternative would be to try to think about the nature of God, and therefore his wishes, from what we see around us. But:
While we argue from the course of nature, and infer a particular intelligent cause, which first bestowed, and still preserves order in the universe, we embrace a principle, which is both uncertain and useless. It is uncertain; because the subject lies entirely beyond the reach of human experience. It is useless; because our knowledge of this cause being derived entirely from the course of nature, we can never, according to the rules of just reasoning, return back from the cause with any new inference, or making additions to the common and experienced course of nature, establish any new principles of conduct and behaviour. (E xi, p.194)
We need a revelation well-authenticated by a divine signature in order to know what God has commanded.