The Three Isomorphisms of David Burrell: Medieval, Modern, and Hybridised accounts of Language and Reality

From its inception, the underlying realism of David Burrell’s (1933-2023) Aquinas:
God and Action has been doubted. 1 This is witnessed to in both the early reviews
and clearly evidenced in the work itself, especially the chapter ‘Truth in Matters
Religious’ and the broader discontent with any quest for certainty that Burrell
expresses. This doubt around Burrell’s realism has only intensified since the birth of
the moniker ‘grammatical thomism’, which situated Burrell’s reading of Aquinas in a
broader trend in theology and ‘revisited’ the realism. 2
This paper will also revisit Burrell’s realism, but instead of finding Burrell’s realism
wanting, it will argue that Aquinas is purposefully ambiguous as to how we might
narrate the relationship between language and reality. This is because Burrell’s work
attempts to address the question of truth by giving a ‘minimum’ standard of
‘isomorphism’ – etymologically ‘sameness of form’ – between language and reality.
This isomorphism is not clearly described by Burrell, but there are clues in his
Aquinas as to three models this isomorphism might take: (1) the metaphysical-
epistemology of traditional Thomism in which a known form is really shared by mind
and reality’ (2) Wilfred Sellars’, in which isomorphism is the ability to map an
environment and has parallels in set theory (a philosophical account given in
dialogue with the Thomist tradition); and (3) finally in Bernard Lonergan’s
isomorphism which retains the parallel with set theory, but also has a stronger
parallel with traditional Thomist metaphysics than Sellars’.
To reiterate, Burrell is purposefully ambiguous. This ambiguity fits with Aquinas’
audience and aim– the work is described in a later foreword by Burrell as a hybrid
between philosophy and theology, between the medieval and the modern. But it also
attempts to reconcile two truths and two requirements Burrell sees in any
philosopher worthy of the name: (1) that one needs to find a latch between language
and reality, however tenuous, and (2) the demand of the philosopher to take the
Kantian “revolution” into account when philosophising today. Burrell’s multiple
models of isomorphism show different paths the philosopher could take while
coherently reading his Aquinas, and remaining faithful to the philosophical tradition
that Burrell situated himself in.