First, the question bears on the distinction between faith and reason and theology and philosophy (and the consequent dismissal of Indian philosophy as a quest for liberation, mystical etc.):

[There is an] often-heard criticism that classical Indian thought cannot be characterised as an intellctually acceptable branch of ‘academic philosophy’ becayse it is entangled with ‘religion’ (p. 14).

And already on the first page, Barua speaks of the parallel condemnation of the medieval Scholasticism and of thinkers like Thomas Aquinas:

The Schoolmen are not ‘philosophers’ because they are Churchmen whose point of departure is a specific Christian world-view, and hence thier learned treatises are to be cognised, as David Hume famously put it, to the withering flames of logical analysis.

Thus,

Anglophone philosophy’s rejection of its internal other, medieval Scholasticism, is paralleled by its suspicion of its external other, Indian darśana —both are supposed to be fatally implicated in Metaphysics, Authority and Tradition (pp. 14–15).

This conclusion supports the more general point that “philosophy is not a natural kind” (p. 6) and that, thus,

Any definition is controversial and already embodies a philosophic attitude (Russell 1975:7, quoted at p. 7).

In this sense, the question at the title of this post opens an exercise in meta-philosophy (“What do we expect ‘philosophy’ to mean?”). As for the possiblity of detecting “philosophy” in India,

as it often happens with the translation of terms which are richly woven into one specific cultural universe into those of another cultural universe, we may argue that terms such as darśana and ānvīkṣikī are ‘not the same, and yet not another’ from philosophia (p. 27).

But this by no means means that one should refrain from using the word “philosophy” while speaking of Indian schools and discussions. On the one hand, as shown by Barua, the soteriological commitment of several Indian schools does not mean that they did not engage in philosophical arguments about the issues deriving from such a commitment (e.g., the nature of reality and of the self). On the other (at last, in the present writer opinion),

As for western philosophers themselves, in the wake of Kuhn and other thinkers who have developed various froms of social epistemology, they have become less shy of speaking of authoritative testimony (pp. 27–28).

As for the sociality of the scientific enterprise, this article focusing on the Western scenario by Dominik Wujastyk is also worth mentioning.

Beside the above, Barua’s essay also deals with several instances of debates both in India and in the West. Barua refers to J. Ganeri’s point that we have to “rescu[e] a story suppressed by Orientalism — the story of reason in a land too often defined as reason’s Other” (Ganeri 2001: 4, quoted at p. 26). Nonetheless, whereas Ganeri and Matilal dealt with the accusation that Indian thought is just mysticism by showing its rigour, Barua recurs to Hadot and shows that also in the West philosophy does not need to be disinterested and pure theoresis. Section “C” is in fact a long discussion of Augustine’s conception of time and of how his philosophical reflections are not “an exercise in idle speculation but are closely related to his exegetical struggles with the Biblical text” (p. 12).

A further, personal comment: Some time ago, a friend has been interviewed for a leader position in an institute for Asian thought. She said she would like the institute to have a “philosophical focus” and one of the people in the committee (who does not work on philosophy) rebutted that using the word “philosophy” could be suspected of a “colonialist attitude”, since “philosophy” is a Western concept. I am sure this objection was well-meant, but I am suspicious of its consequences, namely the implicit statement that only Westerners are able to think philosophically. While thinking we are fair and diversity-aware, we are in fact delegitimizing centuries of philosophical elaborations by refusing to call them “philosophy” just because they happened to take place East of Suez.

CAVEAT LECTOR: These are only my personal reflections on this topic and my reading of Barua’s article. Don’t read in the article anything but what is explicitly said in it.