There seems to be a considerable number of positions meeting the following characteristics: (1) you can pair off the positions according to very broad similarities; (2) the positions are in fact significantly opposed to each other; (3) the opposition primarily depends on the fact that one treats as extrinsic what the other treats as intrinsic. An obvious example of a pair of positions with all of these characteristics is the opposed pair of divine command theory and natural law theory. There are a lot of similarities between the two, to such an extent that people who are being sloppy or who have not seriously looked at either tend to confuse them; but at pretty much every level they are actually opposed to each other, because they are theories of obligation and natural law theory takes obligation to be intrinsic to reason while divine command theory takes it to be extrinsic to reason. There is a kind of reverse symmetry to them, like images in the mirror, where the correspondence of one to the other can be exact and yet opposite as well.
There are many others, however. Here are a few of the most common.
| Extrinsic | Intrinsic | with respect to |
|---|---|---|
| Divine Command Theory (Moral Positivism) | Natural Law Theory | Moral Obligation |
| Legal Positivism | Legal Naturalism (Natural Law Theory) | Authority of Law |
| Occasionalism | Secondary Causes | Causation |
| Intelligent Design Theory | Eutaxiology | Order in Nature |
| Ontologism | Intellectualism | Understanding |
| Platonism | Aristotelianism | Universals |
| Humeanism | Anti-Humeanism | Status of Laws of Nature |
Some of these tend to join up fairly readily; for instance, ontologists tend also to be occasionalists and some form of Platonist. Divine command theorists are always legal positivists, although, of course, the reverse is not true, since a large number of legal positivists are atheists; but a legal positivist who believed in God would by that very fact have very strong reasons for being a divine command theorist. But these kinds of connections are not necessarily true; I know of no ontologist who is a divine command theorist; the implications of ontologism for how we know things would tend to conflict with the easiest options for how we would know about our obligations given a divine command theory. Underlying motivations for accepting a position also have their role to play in the differences. Many people are legal positivists because they think (whether correctly or not) that it sits well with naturalism; nobody is an ontologist because they think that it sits well with naturalism. Occasionalism, ontologism and divine command theory have all at some point or another been taken as superior to their rivals because they are held (correctly or not) to display more fully the glory and power of God. On the other hand, extrinsic can sometimes set up for extrinsic and intrinsic for intrinsic. I, for instance, find myself on the Intrinsic side all the way down the above list, and on the Extrinsic side regard only Platonism as even remotely tempting, and all for similar reasons. There are other pairs you could give where I would fall on the Extrinsic side -- Materialism as opposed to Immaterialism about the relation between perception of the external world and what is ultimately perceived, for instance -- but on most major disputes of this sort I tend to fall on the Intrinsic side of the divide, precisely because I already accept the arguments for the Intrinsic side in a lot of other domains.
There are a few things of interest that tend to come up.
(1) Modalities show up a lot. Necessities and impossibilities (strong modalities) tend to be explicable in either extrinsic or intrinsic ways. For instance, if I say, truly, "I can't do that", you would usually expect this to mean one of two things: Something is making it so I can't or I have an inability even without some external impeding cause. It's not surprising that we get analogous divisions for strong modalities elsewhere. This raises two obvious questions.
(a) Can you establish these kinds of extrinsic/intrinsic mirror positions for all strong modalities? It would be a nice feature if you could, but there are lots of strong modalities for which it is difficult to see how one would get the division in the first place -- Always and Everywhere are the ones that come to mind immediately, since there seems no obvious extrinsic/intrinsic debate on these modalities in particular. On the other hand, there is a distinction between absolute and relational theories for both time and space, which seems to make such a dispute possible, if it were just focused a bit more -- assuming, of course, that you could do so coherently. Perhaps it's already implicit but philosophers just haven't explicitly reached that debate in particular yet.
(b) Do all extrinsic/intrinsic mirror positions end up being about strong modalities in particular? There are a few that seem a bit difficult to put in these terms -- the materialism/immateralism dispute about perception of the external world, mentioned above, for instance. But we get a similar set of issues here as with the prior question -- it may very well be that this is just because, as a matter of historical accident, nobody's gotten around to formulating them that way yet, or, if they have, it never caught on. (The reverse symmetry of the positions doesn't really tell us much on its own about the underlying motivations for focusing on a particular disputable point or accepting a particular position when one does.)
(2) God shows up a lot. It's quite clear that you can get these kinds of mirror positions without talking about God at all. But we do get God in the picture a lot. I think this is for two reasons.
(a) God is the most powerful cause that could enter into any kind of explanation, being the limit case. If there's any cause you could talk about that could in principle do something in either an intrinsic or an extrinsic way, God is certainly going to count. So when God comes up as an explanation for something, it seems you can always ask whether He does so by external or internal causation.
(b) God is the most widely discussed cause. People talk about God a lot, and across a wider range of disciplines and topics than anything else that is likely to come up. To that extent, God's regular appearance in these situations is for the same reason as God's regular appearance in philosophy generally -- God, by the nature of the case, is potentially relevant to a lot of things. There might also be a question of facility -- people seem to process complicated philosophical disputes more easily if put into religious terms. This might be precisely because God is a limit case -- you can drop qualifications you might need to keep track of in other cases -- or because of greater familiarity.
(3) Criticisms of one extrinsic position at least sometimes have analogues in criticism of another, and the same for intrinsic positions. This raises the question of whether it is, in principle, possible to do this across the board. That would be extraordinarily valuable, if true. It is, of course, not necessarily the case that such criticism will be equally plausible across the board, so one might say yes for structural reasons. But the contents of these kinds of disputes are fairly important for how the disputes work, so it could be that some such analogies are blocked completely for content reasons.
