Someśvara is aware of the fact that movements are not enough to detect an intentional action (which he links with effort, prayatna). On the one hand, one can meditate and hardly move, on the other, there can be unintentional movements.
In case a bodily movement is not intentional (in case of a illness, for instance), then it cannot be said to be caused by an effort, maintains Someśvara. One can say that "there is a movement" (spando bhavati), not that "(s)he makes a movement" (spandaṃ karoti).
What about the well-known example "the chariot goes"? Someśvara replies by saying that linguistic use does not always reflect reality. In fact, in khaṭvā (couch) there is a feminine suffix (-ā, technically called ṭāp), although no feminine entity is there, "in the same way, in regard to an unconscious [entity] a verbal suffix is employed although there is no effort" (Nyāyasudhā 1909, p. 579).