  Arguments of this sort are typically met with the following reply: commonalties do not necessarily require common relations to a single entity. Two red things have something in common, in that they are both red, but it does not follow that they bear a common relation to a single entity, the universal of redness. Similarly, two sentences, in virtue of being synonymous, can be said to have something in common, but that fact alone does not entail they are commonly related to a proposition. When a relation R is symmetric and reflexive with respect to a certain domain, it may be useful to speak of the things in the domain which bear R to one another as “having something in common”, but nothing of ontological significance follows. Thus, the conclusion is drawn: we need an argument for thinking that commonalties require common relations to a single entity. 