Oliver Kamm takes Simon Barnes to task:
I understand Oliver to be proposing here a revised definition of the word 'discipline'. What he immediately goes on to say suggests that to be a discipline an area of intellectual activity needs to be involved in the discovery of new truths.
Come off it. Ancient languages - such as Greek, Aramaic and Hebrew - are disciplines. History - ancient, mediaeval and modern - is a discipline. Philosophy is a discipline. And the study of theology may incorporate all of these elements. But theology is not a discipline, because it isn't a branch of intellectual inquiry. How can it be, when the truth is already "known" by revelation?
As one meaning for 'discipline' the New Shorter Oxford gives 'A branch of learning or scholarly instruction'; Merriam-Webster Online gives 'A field of study'. Theology as a branch of learning? As a sphere of scholarly instruction? Of study? I'd say so, yes - all three. One doesn't have to believe in the truth of religious belief to acknowledge this. (These two earlier posts are obliquely relevant.)