0. I continue my investigation of the role of burden-of-proof considerations in philosophy. My ruminations are collected in the aptly titled category, Burden of Proof.
1. Consider a dispute in which one party claims that there are miracles and the other claims that there are no miracles. Where does the burden of proof (BOP) lie? I am open to the suggestion that both claimants incur an obligation to defend their claims if challenged, simply on the ground of having made a claim or advanced a thesis that cannot count as self-evident or foundational in the way in which the Law of Non-Contradiction is foundational. But if both have an obligation (dialectical if not moral) to defend their respective claims if challenged, on pain of being deemed unreasonable if they refuse to do so, that is not to say that both shoulder a burden of proof (BOP). For if I maintain that p and you maintain that ~p, and each of us has a burden of proof, then, given the correlativity of BOP and defeasible presumption (DP) lately explained, there is a defeasible presumption in favor of both p and ~p in the dialectical situation in which we confront each other -- and that is absurd. In the context of a proceeding wherein the goal is to settle whether a proposition or its negation are true it cannot be provisionally assumed both that the proposition and its negation are true.
So we need to distinguish between the (dialectical if not moral) obligation to defend one's assertions, an obligation one incurs whether one asserts or counter-asserts, and burden of proof. Thus we talk of the burden of proof in a dialectical proceeding. It presses down on one interlocutor or the other, but not both, if it presses down on either.
What I want to resist, however, is the notion that there is a fact of the matter as to where the BOP lies. I want to suggest that there is no context-independent fact as to which side shoulders the BOP. As a consequence, arguing about where the BOP lies in philosophical debates is as pointless and out-of-place as arguing in a court of law whether the BOP is on the prosecution/plaintiff or on the defense. That the onus probandi lies on the former is constitutive of the courtroom 'game,' at least in the Anglosphere. As constitutive, it is not up for grabs in the legal context.
2. Some think that whoever who makes a positive claim assumes a BOP. But we should beware of the ambiguity of 'positive claim.' Are we referring to the content of a claim, or the claiming of the content? Are we talking logic or dialectics? 'There are miracles' is logically affirmative while 'There are no miracles' is logically negative. And this quite apart from the dialectical situation in which alone it is appropriate to speak of presumptions and probative burdens. The propositions expressed by those sentences are the contents of the respective claims or assertions. But both the miracle-affirmer and the miracle-denier are making a positive claim in that they are both positively claiming something. A counter-assertion is just as much of an assertion as an assertion.
If one makes a claim (advances a thesis, asserts something, etc.), then one does so regardless of whether the content of the claim is logically affirmative or logically negative. So why should the onus probandi rest on the one who asserts that there are miracles and not on the one who asserts the opposite? Since both make a claim, both reasonably incur the obligation to defend the claim if challenged. I am not assuming dialectical egalitarianism according to which, as Michael Rescorla puts it, "every asserted proposition requires defence when challenged by an interlocutor." There may be propositions that need no defense. I am only assuming that the propositions we are discussing can both be reasonably challenged.
3. One cannot therefore in general hold that only those who make assertions the content of which is logically affirmative assume a burden of proof. This may also be appreciated from the fact that some logically negative propositions entail logically affirmative ones. If there are no miracles, then there are no violations/suspensions of natural causal laws. If there are no such violations, then nature is a causally closed system into which nothing enters and nothing escapes. But 'Nature is causally closed' is logically affirmative. The naturalist who claims that there are no miracles is also committed to claiming that nature is causally closed. Clearly, if he bears a burden of proof with respect to the latter proposition then he bears it with respect to the former one as well.
4. So where does the BOP lie if it doesn't lie on the one the content of whose assertion is logically affirmative? Does it lie on the one who calls into question received opinion? That cannot be right either, enshrining as it does an extreme inquiry-inimical doxastic conservatism. The way 'burden of proof' is standardly used, the BOP lies on one party or the other but not both. But I fail to see why in the miracle case or any other it rests on one side rather than the other. I suggest, in line with what I maintained day before yesterday, that there is no fact of the matter as to where the BOP lies. It is a matter of decision, if not by an individual, then by a community.
5. So let's consider the scientific community. The members of this community are bound together by common goals and methods. The 'game' of natural science is played according to game-constitutive rules. One of these rules is that in natural science there can be no appeal to anything supernatural: everything that science explains -- everything in nature -- is to be explained using only other 'stuff' in nature, smaller 'stuff,' earlier 'stuff.' Thus the tides are explained in terms of the moon and its gravitational effect; earthquakes in terms of tectonic plate shifts; diseases in terms of viruses, etc.
For one who plays the scientific 'game' and abides by its rules, there is no question but that the burden of proof lies on the one who asserts that there are miracles. No scientist worth his salt could hold that there is a presumption in favor of the existence of miracles. It is the other way around: there is an exceedingly strong, if not quite indefeasible, presumption in favor of their nonexistence, and indeed of the nonexistence of anything nonnatural. But this onus-assignment is relative to the scientific 'game' and partially constitutive of it.
6. My point, then, is that BOP-assignments are context- and community-relative and depend on conventions that members of these communities collectively adopt. In the legal context the BOP is on the prosecution while in the science arena, where methodological naturalism rules, the BOP is on anti-naturalists: those who defend miracles, the existence of God and the soul, the libertarian freedom of the will, etc. But the science 'game' is not the only game in town. There is the religious 'game.' No one who takes the latter seriously could possibly think that science delivers the ultimate metaphysical low-down. Relative to the religious 'game,' the BOP will be on atheists.
And then there is the moral 'game.' Most of us play it: we think in moral categories and we cannot imagine not thinking in them. We speak of right and wrong, good and evil; we hold ourselves and others morally and not just causally responsible for what we do and leave undone. We judge and we are prepared to be judged. We praise, we blame, we distinguish among the impermissible, the permissible, the obligatory, and the supererogatory. We subject our thoughts, words, deeds, institutions and laws to moral evaluation. Committed as we are to moral responsibility, we are committed to the freedom of the will. So, from within the moral 'game,' it is clear that there is a presumption in favor of the freedom of the will so that the burden of proof lies squarely and nonnegotiably on the shoulders of those who would deny it.
My suggestion is that it makes no sense to ask where the BOP really lies, on, say, the moralist or on the one who holds that morality and its presuppositions (freedom of the will, etc.) are illusory and without standing in a physical world. The moral way of thinking brings with it a presumption in favor of the reality of its categories, a presumption which, if defeasible, is just barely so. The scientistic way of thinking brings with it an opposite presumption.
So instead of arguing the procedural question as to who has the BOP in a philosophical dispute one should simply get to work and make one's case.