Matthew Hopper, in discussing how the term “conversion” is appropriate for Paul, notes that
“The decision Paul sought was a decision to swear fealty to King Jesus and become a citizen of his people by means of baptism. It was not a matter of ‘beginning an intimate relationship with Jesus’… as the result of dramatic, impulsive emotions.”
Yes: this should be taken as a given: Paul wasn’t a soul-searching western. But just because he didn’t convert for introspective reasons doesn’t mean that he didn’t convert at all. Matthew understands this, unlike (say) Krister Stendahl.
There are three sides to the question of Paul’s conversion: (1) an objectively-analytical point of view, (2) mainstream Judaism’s point of view, and (3) Paul’s own point of view. According to the first two, I would say yes: Paul should be understood as a convert to something radically new. But if we listen to Paul himself, I think the answer becomes more murky; both yes and no. Let’s take them in turn.
(1) Required reading is Zeba Crook’s Reconceptualising Conversion, in which the author demonstrates that by the time of Hellenistic Judaism, it was possible to be called and thus converted: Paul was invoking the call of the divine patron-benefactor (which involved conversion by definition) and the call of the Hebrew prophets at the same time. In other words, Stendahl’s distinction between being “called” and “converted” (recently followed by Malina and Pilch) is a false dichotomy. Objectively speaking — and by non-introspective standards — we can and should speak of Paul’s conversion.
(2) Even assuming a valid distinction between being “called” and “converted” (just for the sake of argument) doesn’t settle the issue, because while Paul naturally aligns himself with prophets like Isaiah and Jeremiah, his rivals easily denied him his claims. Most of his contemporaries thought he was a radical apostate (on which see Philip Esler’s Galatians).
(3) Paul’s own view of the matter is tricky. On the one hand, he knows he has found something new, but on the other, his patron-deity hasn’t changed. Zeba Crook discusses the phenomenon of synkrisis. In order to credit benefactors, clients always described their past as grim and bleak in comparison to the new and improved present — except in cases where the patron doesn’t change, in which case they “raise the stakes” by improving upon an already excellent past which in comparison to the present is actually worse than worthless. Says Crook:
If patronal synkrisis was meant to honor the patron by attributing to him or her a tremendous improvement in life by comparing the good one has received to the ill one knew previously, then Paul’s synkrisis in Philippians does this all the more so… All that he has lost from his past he now regards as “shit”…Paul’s past was excellent; it was a source of pride for him. Yet in comparison with Paul’s awesome present status, even something as excellent as that appears so profoundly diminished as to call it “shit”. (pp 181-182)
That’s the irony we’re stuck with. When a patron-deity stays the same after conversion, the past must remain positive and yet become worse-than-worthless at the same time. So Paul’s Jewish heritage is good in and of itself (Philip 3:4b-6), but nothing more than “shit” when compared to the new revelations of Christ (Philip 3:7-11).
Paul knew that he was advocating something radically new with his version of the Christ-gospel, but he was caught between loyalty to past and present convictions — again, he was still serving YHWH. I appreciate the way James Dunn characterizes the so-called “continuity” presented in Rom 9:6-10:21: “continuity by transformation, as when a caterpillar becomes a butterly, and the empty shell of the caterpillar is all that’s left of the old stage of existence”. It may be an ingenious argument by sectarian standards, but any mainstream outsider would have laughed themselves sick and treated it with the derision it deserved. So Paul capped it off with Rom 11:1-32, making clear that “continuity by extension” is what he really had in mind — an olive tree rather than a butterfly. There will never be an easy way to resolve this tension. Who said being a convert was easy?