 The status of second-order quantification remains controversial. The standard model theory for second-order quantification states the truth conditions of a formula of the form \(\forall X\,A\) in terms of ordinary quantification over subsets of the domain. This may have inclined some to agree with Quine (1986) that second-order quantification is only intelligible as covert first-order quantification over sets. Second-order logic would, on this view, be best conceived as a species of two-sorted first-order set theory. But the model-theoretic interpretation is not the only, much less the intended interpretation of second-order quantification. Indeed, Boolos (1984) proposed an alternative interpretation of monadic second-order logic in terms of an ingenious translation into a fragment of natural language on which second-order quantifiers became plural quantifiers on which more below. There is an even more radical alternative, which is to deny that the interpretation of second-order quantification should be determined by either the model theory for second-order logic or by means of any explicit or tacit translation into some fragment of natural language. Instead, the thought continues, one may have to rely a more direct method and learn what second-order quantifiers mean through immersion and triangulation with natural language. For we understand what is meant by quantification into the position of a singular term in a predication in natural language. That constrains the interpretation of second-order quantification, which stands to predicates as first-order quantification stands to singular terms. This is similar to the approach one finds in Prior 1971 (Ch. 3) and Williamson 2003.