 However, let’s assume that the defenders of the Direct Argument are right that  (18)  does not entail  (21).  What would follow? It would follow that  (18)  does not incur any additional ontological commitments of the sort that can be incurred by singular first-order quantifiers. But this conclusion falls short of the argument’s desired conclusion that  (18)  does not incur any additional ontological commitments of any sort. In order to get from the actual conclusion to the desired one, we would in addition have to assume that all ontological commitments are of the sort incurred by singular first-order quantifiers. But there is an influential philosophical tradition that denies this assumption and instead holds that all kinds of quantifiers incur ontological commitments, not just singular first-order  ones.[15]  The most famous exponent of this tradition is Frege, who claims that second-order quantifiers are committed to concepts, just as singular first-order quantifiers are committed to objects. This tradition ties the notion of ontological commitment very closely to that of a semantic value. This will be the topic of the next and final subsection.