ABSTRACT
This chapter explains the problem of theoretical terms by reference to a certain disposition term D. Sometimes a special class of transcendental terms is singled out for separate treatment in connection with this problem. The chapter notes that disposition terms typically apply within the range of E's ontology as already determined by choice of its observational vocabulary. The predicate 'is an electron' not only seems itself non-observational and resistant to definition by observational primitives; it furthermore purports to denote things outside the range of our hitherto determined ontology. For the expansion of a hitherto determined ontology does not in itself appear objectionable; addition of a new observational term may have the same effect, for example. The possibility of introduction by means of reduction sentences thus fails to draw a significant line between dispositional and transcendental terms.
