According to Peter Martens the role of the philologist included the following (42):
Literary and historical analysis (ἐξηγητικόν)
Aesthetic and moral evaluation (κρίσις ποιημάτων)
In chapter two of his book Martens goes on to show how Origen used these methods in his own interpretation of scripture. I found it to be a very helpful chapter explaining some of Origen’s exegetical methods. He concludes:
For Origen there were in principle two referents of any given scriptural text: the literal and the “nonliteral” (i.e., allegorical figurative, symbolic, spiritual, mystical or deeper). Ideal philologists pursed a broad education and cultivated a series of exegetical techniques with the intent of deciphering both the literal and the allegorical referents of a passage. Philology, in other words, could be practiced in a literal or an allegorical mode — but it was always philology (63).
Upon completion of this book I will be writing a full review on it. Thanks to Oxford University Press for the review copy.