 There are two lines of response to this worry (whose earliest formulations go as far back as V. Lowe 1953). First, it could be observed that the ontological exuberance associated with the relevant composition principles is not substantive—that the increase of entities in the domain of a mereological theory cum composition principles involves no substantive additional commitments besides those already involved in the underlying theory without composition. This is obvious in the case of modest principles in the spirit of (P.11ξ) and (P.14ψ), to the effect that all suitably related entities must have an upper bound. After all, there are small things and there are large things, and to say that we can always find a large thing encompassing any given small things of the right sort is not to say much. But the same could be said with respect to those stronger principles that require the large thing to be composed exactly of the small things—to be their mereological sum in some sense or other. At least, this seems reasonable in the presence of extensionality. For in that case it can be argued that even a sum is, in an important sense, nothing over and above its constituent parts. The sum is just the parts “taken together” (Baxter 1998a: 193); it is the parts “counted loosely” (Baxter 1988b: 580); it is, effectively, “the same portion of Reality” (Lewis 1991: 81), which is strictly a multitude and loosely a single thing. That's why, if you proceed with a six-pack of beer to the six-items-or-fewer checkout line at the grocery store, the cashier is not supposed to protest your use of the line on the ground that you have seven items: either s/he'll count the six bottles, or s/he'll count the one pack. This thesis, known in the literature as “composition as identity”, is by no means uncontroversial and admits of different formulations (see van Inwagen 1994, Yi 1999, Merricks 1999, McDaniel 2008, Berto and Carrara 2009, Carrara and Martino 2011, Cameron 2012, Wallace 2013, Cotnoir 2013a, Hawley 2013, and the essays in Baxter and Cotnoir 2014). To the extent that the thesis is accepted, however, the charge of ontological exuberance loses its force. The additional entities postulated by the sum axioms would not be a genuine addition to being; they would be, in Armstrong's phrase, an “ontological free lunch” (1997: 13). In fact, if composition is in some sense a form of identity, then the charge of ontological extravagance discussed in connection with unrestricted composition loses its force, too. For if a sum is nothing over and above its constituent proper parts, whatever they are, and if the latter are all right, then there is nothing extravagant in countenancing the former: it just is them, whatever they are. (This is not to say that unrestricted composition is entailed by the thesis that composition is identity; indeed, see McDaniel 2010 for an argument to the effect that it isn't.)