 One possible way out of this kind of case is to say that the sword is a phase of the walking stick, thereby introducing ad hoc phase sortals. By the expression ‘ad hoc phase sortal’ I mean a sortal that can be used sometimes as a phase sortal, designating an object only through part of its existence, and sometimes as an ultimate sortal, designating an object through the whole of its existence. Of course, even a normal phase sortal might, contingently, in a given instance, designate an object through the whole of its existence. One might say that the phase sortal baby could designate something through the whole of its existence if, for example, a human being died at the age of six months and hence never got beyond babyhood. But it remains the case that, by dint of the meaning of the term, a baby is a phase of a human being (or, perhaps, some other animal) even when a particular creature fails to get beyond that phase. A sword is not, however, in virtue of the meaning of the word ‘sword’, a phase of anything, and to use the term to name a phase of something in a given case, when it suits, is ad hoc. Allowing sortals of this kind would put the concept of sortal under pressure, for an ultimate sortal was originally thought to be a kind of concept that necessarily characterises an object present-tensedly throughout its existence, not a concept that sometimes does and sometimes does not. If it were possible for a given sortal, such as sword, sometimes to be an ultimate sortal and sometimes a phase sortal, it is not clear how such an expression would differ from an expression such as brown thing, which may or may not characterise something through the whole of its existence. But it is vital that the distinction between sortals, phase or ultimate, and expressions such as brown thing be clearly maintained, if the notion of sortal is to serve any formal purpose.