Robert Adams has defended an argument against the pre-existence of singular propositions about oneself on the grounds that it would have been possible for them to have existed even if one had never existed, which is absurd. But the crucial assumption underlying this reasoning, namely, that the only histories of a world which are possible at any time are continuations of that history up to that time, is false, as shown by the illustration of time travel. Furthermore, if Adams were correct, fatalism would follow. The failure of Adams's argument has important implications for the Molinist doctrine of divine middle knowledge.
See my related article "Robert Adams's New Anti-Molinist Argument" .
"Adams on Actualism and Presentism." Philosophia 25 (1997): 401-405.
In his article, "Time and Thisness," Robert Adams had argued, "My thisness, and singular propositions about me, cannot have pre-existed me because if they had, it would have been possible for them to have existed even if I had never existed, and that is not possible."{1} Jonathan Kvanvig has charged, however, that this reasoning is susceptible to the same response as is the argument for fatalism.{2} Just as we have the power to act in such a way that were we to do so, future-tense propositions which were in fact true would not have been true, so things can happen differently than they will, in which case thisnesses and singular propositions which in fact exist(ed) would not have existed. While acknowledging the philosophical respectability of Kvanvig's position, Adams in his reply to Kvanvig sticks by his argument, observing that while he agrees "that things can be true about a time that would not have been true about it if . . . things had gone differently at a later time" and "that there are facts about 1935 . . . that could not have obtained if I had not been born later," still he thinks that we should not admit to our primitive ontology entities that depend on later events for their very existence.{3}
But why should we think that the existence of things in the past cannot be counterfactually conditioned by future events? Adams states that the intuitive basis of his position lies in
. . . the appeal of the idea of metaphysically possible continuations of the history of any possible world from any time t, whose variation (since they are continuations) can affect what beings contingently come into existence after t, but cannot affect what exists at or before t . . . My claim . . . is only that whatever exists in the history of W up until t must be metaphysically compatible with any possible continuation of that history after t.{4}
This is a powerful intuition; but a little reflection reveals that the power of its appeal springs from the fact that it is in reality an analytic truth. For by definition various future histories later than t are continuations of the history earlier than t if and only if they include that history as their past. That is just what it means to be a continuation of a history. Not only all entities prior to t must remain unaffected, but also all events in their temporal and spatial locations. Otherwise the histories later than t would be continuations of different histories. But from this analytic truth, the crucial inference does not follow that at any time t in a world W, all metaphysically possible histories later than t have the same history earlier than t. In other words, those histories which are continuations of the history earlier than t are only a proper subset of all the future histories possible at t. For example, consider the history of a world up to t which includes the appearance of a time traveller from a time later than t:
At the time of t, various future histories are metaphysically possible, including what we can infer to be the actual future history b, d, e, which is a continuation of the history a, b. But at t other future histories are also possible, like b, c, which are not continuations of a, b. Given our knowledge of the past history a, b, the path of the future until the time traveller's departure is certain (in the epistemic sense), but not necessary. If b, c were the path taken instead, then the time traveller would not have appeared prior to t and so the history a, b would have been different. It is a necessary truth that the actual future is a continuation of the actual past, but it does not follow that every possible future is a continuation of the actual past.
Finally, I think we should do well to challenge Adams's artificial bifurcation between entities and facts or truths. If tense is an objective feature of reality, as Adams and the presentist agree, then there are tensed facts which are every bit as much a part of any actual world's history as are entities. In possible worlds semantics tense is necessarily neglected because, as we learn from McTaggart's Paradox, there can be no maximal description of a world in tensed language.{5} In speaking of the history of any possible world W up until or from t, Adams thus overlooks the tense which is an essential feature of the exemplification of any world in which time exists. In any instantiation of a temporal world there will be tensed states of affairs that obtain in addition to the entities that exist (e.g., Its being presently tn). If, then, future contingent propositions are bivalent, to what do they correspond? Even if we say that their truth is ultimately grounded in the future truth of their respective present-tense versions, they do not correspond to those present-tense states of affairs. Rather a view of truth as correspondence requires that they correspond to future-tense states of affairs which obtain right now. Since the history of any concrete temporal world includes such tensed states of affairs, it follows that all continuations of that history must include the same past states of affairs. If Adams is right that all future histories possible at t are continuations of the past history at t, then fatalism follows. If, to escape fatalism, we allow possible future histories to include those involving different past-tense states of affairs, then a similar recourse must be open to the defender of thisnesses and singular propositions.{6}
Endnotes
{1} Robert Merrihew Adams, "Time and Thisness," Midwest Studies in Philosophy 11 (1986): 317.
{2} Jonathan L. Kvanvig, "Adams on Actualism and Presentism," Philosophy and Phenomenological Research 50 (1989): 89-98.
{3} Robert Merrihew Adams, "Reply to Kvanvig," Philosophy and Phenomenological Research 50 (1989): 300 (my emphasis).
{4} Ibid., pp. 299-300.
{5} See Michael Dummett, "A Defense of McTaggart's Proof of the Unreality of Time," Philosophical Review 69 (1960): 503.
{6} Such a recourse must also be open, pari passu, to the Molinist, whose doctrine of middle knowledge has been criticized by Adams on similar grounds. According to that doctrine God knows logically prior to His creative decree the truth of certain subjunctive conditionals concerning how creatures would freely act in any circumstances in which God might place them. Adams objects:
"Suppose it is not only true that P would do A if placed in circumstances C; suppose that truth was settled, as Molinism implies, prior to God's deciding what, if anything, to create, and it would therefore have been a truth even if P had never been in C--indeed even if P had never existed. Then it is hard to see how it can be up to P to determine freely whether P does A in C" (Robert Adams, "An Anti-Molinist Argument," Philosophical Perspectives 5 [1991]: 356).
The argument seems to assume as a premiss that there is a true counterfactual of creaturely freedom 
with a true antecedent: If P were in C, P would do A. Adams seems to assert that P cannot freely bring about the truth of because if, posterior to God's middle knowledge of , P were not in C or did not exist at all, would still be true, though P never does A in C, which is absurd. This argument is parallel to the issue under discussion, counterfactuals of creaturely freedom and divine middle knowledge taking the place of thisnesses and singular propositions. A Molinist who holds that in the case of a true counterfactual with a true antecedent it is the agent who, by doing what the consequent states, freely brings about the truth of the counterfactual would also hold that if P failed to be in C, 's truth would not have been brought about by P. That does nothing to disprove the claim that 's truth is, in fact, freely brought about by P. It is within our power so to act that were we to do so, the truth of counterfactuals of creaturely freedom which is brought about by us would not have been brought about by us.
Moreover, if Adams's distinction between entities and facts or truths successfully averts fatalism, it would also undermine Adams's anti-Molinist argument, for the truth of counterfactuals of creaturely freedom is more akin to the truth of future contingent propositions than the existence of singular propositions. All entities and even truths in the past would remain the same were P not to be in C; all that would be different is that the counterfactuals in question would no longer stand in the relation to P of "being brought about to be true by."
I should go even further and claim that we have it within our power to act in such a way that, were we to act in that way, different counterfactuals of creaturely freedom would have been true and so God's middle knowledge would have been different. Perhaps Adams would say that God's beliefs count as entities; if so, then if God has beliefs (but see William Alston, "Does God Have Beliefs?" Religious Studies 22 [1986]: 287-306) about not only conditional future contingents, but even absolute future contingents, His knowledge of both of these (assuming the soundness of Adams's argument) is still at worst inerrant, though fallible. Adams's anti-Molinist argument requires that it be more essential to theism to maintain the infallibility (as opposed to inerrancy) of God's beliefs than to preserve His foreknowledge and/or middle knowledge, which seems a very odd estimate of theological priorities.
