Within Rāmānujācārya's Tantrarahasya's discussion about the meaning of exhorative suffixes (liṅādi), an objector proposes that the apūrva implies the action (TR IV §3.12). This means that the apūrva should possibly be denoted according to its own nature (svarūpa), that is, independent of an action. This possibility is withdrawn since:
• implication –like metaphore– presupposes that one already knows about the connection between the implier and the implied entity. But this cannot be the case in regard to apūrva and eﬀort.
• the apūrva cannot be denoted according to its own nature, because its own nature depends, in order to be realised, on the action.
One might wonder why is metaphore possible and implication impossible. In other words, why is it possible that one gets at action through metaphore via apūrva, whereas the same action cannot be implied by the apūrva? I have not yet found a comparative discussion about the two, but I think they work in the following two ways:
liṅ etc. → apūrva
→ (apūrva) ⇒ action
liṅ etc. → apūrva
(with → indicating primary denotation and ⇒ indicating secondary denotation)
The second case seems to be excluded because it is not possible that the apūrva in itself signiﬁes the action, whereas it is possible that the exhortative suﬀixes secondarily denote it, through its link with apūrva. But why is the apūrva-action link enough for metaphore and not for implication? The only hint one ﬁnds in the text (§3.12) is that to the lack of an explicit (Vedic) statement enabling the implication. This might refer to the fact that the link between action and agent (the acceptable instance of implication) is proved through sense-perception. Since, however, sense-perception cannot attain apūrva, one
can only know about its links through a Vedic statement (śabda). Unfortunately, no such Vedic statement exists. On the other hand, metaphore is possible because the action is already within what can be denoted by the exhortative suﬀixes, though secondarily. As soon as one realises that the apūrva is not at the moment denoted, one immediately turns to the next potential meaning of the exhortative suﬀixes, i.e., the action.
Summing up, the apūrva cannot by itself imply anything, since there is no instrument of knowledge about it. On the other hand, exhortative suﬀixes denote primarily the apūrva but, in case this is not the meaning, the action.