Everyone must read Cardona's work on Pāṇini and one cannot go without him if one wants to understand something about Pāṇinian grammar. However, until now I was not an unconditioned estimator of his written work, since this is often very technical.
Yesterday, however, I had the real pleasure of listening to his talk at the WSC, which is was terrific. Not only he made his point very clearly, he is an amazing speaker, both in English and in the following debate in Sanskrit. The following is a short summary of the main argument:
In the case of anubhū- and of the other verbs-cum-preverbs, the aṅga for augment, reduplication, etc. is bhū-, not anubhū-. Hence, for grammatical purposes, dhātus (verbal roots) and upasargas (preverbs) are to be considered as separate padas (words). By contrast, from the semantic point of view they are to be considered as a single pada, since the meaning of anubhū- is different from that of anu+bhū-.
Semantically, anubhū- is a separate dhātu, grammatically, it is not. But how could the two stances coexist? Grammarians and lexicographers needed to achieve a compromise and in fact they achieved an interesting one: We treat the verb as if it had multiple meanings and upasargas as only dyotakas ('illuminator'). The rationale is that preverbs only help the listener to focus on one of the meanings the root already had in itself. Hence, it does not make sense to speak in absolute terms of whether something is X or Y. All depends on what is your aim!
In short, once again, we have to do with a functionalist approach against an ontological one (this last line is obviously mine).
DELENDA CARTHAGO: No one is forced to deliver a paper in a conference. Hence, if one decides to do it, why not preparing, so that one can avoid reading or at least recite one's written text?