In this paper I will present three arguments (based on the notions of constitution, metaphysical reality, and truth, respectively) with the aim of shedding some new light on the structure of Fine's (2005Fine's ( , 2006 'McTaggartian' arguments against the reality of tense. Along the way, I will also (i) draw a novel map of the main realist positions about tense, (ii) unearth a previously unnoticed but potentially interesting form of external relativism (which I will label 'hyper-presentism') and (iii) sketch a novel interpretation of Fine's fragmentalism (which I contrast with Lipman's 2015, 2016b, forthcoming).

According to Mereological Nihilism, nothing has proper parts. In this note it is argued that Composition is Identity can be shown to entail Mereological Nihilism in a much more simple and direct way than the one recently proposed by Claudio Calosi.

In this paper I address two important objections to the theory called '(Strong) Composition as Identity' ('CAI'): the 'wall-bricks-and-atoms problem' ('WaBrA problem'), and the claim that CAI entails mereological nihilism. I aim to argue that the best version of CAI capable of addressing both problems is the theory I will call 'Atomic Composition as Identity' ('ACAI') which consists in taking the plural quantifier to range only over proper pluralities of mereological atoms and every non-atomic entity to be identical to the (proper) plurality of atoms it fuses. I will proceed in three main steps. First, I will defend Sider's (2014) idea of weakening the comprehension principle for pluralities and I will show that (pace Calosi 2016a) it can ward off both the WaBrA problem and the threat of mereological nihilism. Second, I will argue that CAI-theorists should uphold an 'atomic comprehension principle' which, jointly with CAI, entails that there are only proper pluralities of mereological atoms. Finally, I will present a novel reading of the 'one of' relation that not only avoids the problems presented by Yi (1999aYi ( , 2014 and Calosi (2016bCalosi ( , 2018 but can also help ACAI-theorists to make sense of the idea that a composite entity is both one and many. Keywords Mereology • Composition as Identity • Collapse • Mereological Nihilism1 '[…] perhaps the major motivation for CAI is that it implies the 'ontological innocence' of classical mereology' (Cotnoir 2014: 7). 'If Lewis's claim were that the fusion is literally identical to the cats that compose it, he would clearly be entitled to ontological innocence' (Bennett 2015: 256). '[…] the thought that a fusion is numerically identical to the things that compose it taken together […] would vindicate the intuition that such double countenancing is ultimately redundant, hence the innocence thesis' (Varzi 2014: 49). 'But why think that mereology is ontologically innocent? If composition is identity, then ontological innocence is secured' (Hawley 2014: 72).

According to 'Strong Composition as Identity' (SCAI), if an entity is composed of a plurality of entities, it is identical to them. As it has been argued in the literature, SCAI appears to give rise to some serious problems which seem to suggest that SCAItheorists should take their plural quantifier to be governed by some 'weak' plural comprehension principle and, thus, 'exclude' some kinds of pluralities from their plural ontology. The aim of this paper is to argue that, contrary to what may appear at first sight, the assumption of a weak plural comprehension principle is perfectly compatible with plural logic and the common uses of plural quantification. As I aim to show, SCAI-theorists can simply claim that their theory must be understood as formulated by means of the most 'joint-carving' plural quantifier, thus leaving open the possibility of other, less joint-carving, 'unrestricted' plural quantifiers. In the final part of the paper I will also suggest that SCAI-theorists should not only allow for singular quantification over pluralities of entities, but also for plural quantification over 'super-pluralities' of entities.

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