Eternalism vs. Presentism

PrefaceThanks again to That1User for accepting. I would like to remind him that according to the structure of this debate he, Con, was supposed to present his arguments right away. "In round one and two respectively Con and Pro are going to present their case"Since I expected a shorter debate I am going to present only two arguments in favor of eternalism and against presentism.The Argument from Special RelativityThe argument at hand is inspired by and a extended version of the argument from Metaphysics: An Introduction by Alyssa Ney(1).P1) If presentism is true, then which objects or events are real depends on which are past, present, or future. (from the definition of presentism)P2) But which objects and events are past, present, or future depends on facts about which events are simultaneous with the here and now. (from the definitions of ‘past,’ ‘present,’ and ‘future’) P3) If the special theory of relativity is true, then which events are simultaneous with the here and now is a matter of one’s perspective. (consequence of Special Relativity)P4) The special theory of relativity is true.P5) So, which events are simultaneous with the here and now is a matter of one’s perspective. (by premises (3), (4), and modus ponens)P6) So which objects and events are past, present, or future is a matter of one’s perspective. (from premises (2) and (5))P7) So if presentism is true, then which objects or events are real is a matter of one’s perspective. (from (1) and (6)) P8) But what is real is not a matter of one’s perspective.C1) Therefore, presentism is false.Premises 1), 2) and 3) should be uncontroversial as they are all true by definition. 4) is of course challengable, but this would require an alternative theory compatible with lenght contraction and time dilation (among other things) whilst also being compatible with presentism. 5), 6) and 7) are inferences. I can't present a rocksolid argument for 8), other than the reductio that denying it leads to absurd conclusions, some of which I am going to set forth in my other argument. P9) Eternalismism is true, if and only if which objects or events are real is not a matter of one’s perspective. (from the definition of eternalism)C2) Therefore, eternalism is true. (from (8) and (9), equivalence and modus ponens)'One's perspective' should of course be understood as 'one's reference frame'.The Truthmaker ObjectionPresentism has a very intuitive side and a very counterintuitive one. For example it intuitively makes sense to say that the proposition "dinosaurs exist" is wrong. This is compatible with presentism as only present objects exist. However what is rather difficult for a presentist is to make sense of propositions like 'once dinosaurs roamed the earth'. Typically presentists want to allow some talk about past and future events and therefore introduce tense operators like 'WAS(Φ)' and 'WILL(Φ)', which can be informally expressed as "At some past time t, Φ was is true at t" and "At some future time t, Φ is true at t" respectively. For example 'Once dinosaurs roamed the earth' could be translated into 'WAS (Dinosaurs roam the earth)'. These operators are not ontologically committing.The question remains in virtue of what these operators are ture. States of affairs? Impossible, under presentism there is no past state of affairs where dinosaurs roam the earth.The Truth-Maker Principle: For every truth, T, there exists an entity -a truth-maker- who's existence suffices for the truth of T.(2)This is of course an outdated principle, as it faces difficulties with negative existentials. However, modern (modal) principles such as David Lewis' claim that truth supervenes on being are much more difficult to grasp and don't get the point across any better than the truth-maker principle(3).The raison d'etre (DDO doesn't allow for the proper spelling) for such principles is to rule out dubious ontologies with a lot of ungrounded truths, like "brute counterfactuals", with no connection to reality.Truth doesn't "float free", but it seems like the presentist is commited to say that it does in case of his tensed language, making it a bunch of brute facts.Brute Fact: A fact that can be understood, but not be explained. E.g. the fact that identity workds the way it does.Philosopher and mathematician, Alexander Pruss notes "[c]laiming [something] to be a brute fact should be a last resort. It would undercut the practice of science."(4) If the presentist is right, then all of our regular talk about what we did yesterday or last week, or will do next weekend or next summer is true in virtue of being an unexplainable brute fact of reality! That seems unacceptable. Eternalism faces no such problems.Sources(1) Alyssa Ney, Metaphysics: An Introduction, p.143f(2) Theodore Sider, Four-Dimensionalism, p.36(3) David Lewis, On The Plurality of Worlds, (the page is not displayed on my kindle)(4) Alexander R. Pruss, The Hume-Edwards Principle and the Cosmological Argument, in Gale and Pruss, 2003: 347–363