It refers back to a review by Bhikkhu Bodhi
of Gombrich's book "How Buddhism Began: The Conditioned Genesis of the Early Teachings".
It is curious that in Chapter IV: Retracing an ancient debate: how insight worsted concentration in the Pali Canon Gombrich seems to think that "dry insight" (without Jhana) means not doing formal meditation at all. This would be news to modern "Insight" meditators, following the techniques taught by Sayadaw Mahasi, Goenka, etc...
From Bhikku Bodhi's review:
My second objection is to his insistence on interpreting alternative approaches to the path advocated in the suttas as competitive opposites. Thus, because the canon recognizes two types of arahants, those "liberated in both ways" and those "liberated by wisdom," Gombrich holds that a debate was underway between those monks who favoured meditation and those who thought insight was so far superior that meditation could be dispensed with. He appeals for support to the Susīma Sutta (SN 12:70), which he reads as implying that enlightenment can be attained without meditation (pp. 125_26).
This sort of dialog between the "Academic Scholarship" of Professor Gombrich and the "Monastic Schoarship" of Bhikkhu Bhodhi (which extends to the footnotes in Bhikkhu Bodhi's translation of the Samyutta Nikaya) is useful and stimulating. It's just a pity that the timescale is so long. A thread on DhammaWheel with the Venerable and the Professor going head to head would be very entertaining...