Increasingly, nurses conduct scientific inquiry into complex health-care problems by collaborating on teams with researchers from other highly specialized fields. As cross-disciplinary research proliferates and becomes institutionalized globally, researchers will increasingly encounter the need to integrate their particular research perspectives within inquiries without sacrificing the potential contributions of their discipline-specific expertise. The work of the philosopher Bernard Lonergan (1904–1984) offers the necessary philosophical grounding. Here, I defend a role for philosophy in cross-disciplinary research and present selected ideas in Lonergan's work. These include: (1) a dynamic, normative pattern that each inquirer operates uniquely also forms the common core, or unity, in knowing; (2) the possibility of cross-disciplinary knowledge development is dependent on each researcher's consciousness of her or his attentiveness, intelligence, reasonableness, and responsibleness; and (3) shifts in researchers' viewpoints, or horizons, facilitate their collaborative inquiry and their grasp of the unity in knowing. The desire to know, shared by team members, drives their inquiry. Lonergan's stance is consistent with nursing values because it respects, but does not unconditionally privilege, any researcher or discipline. Arguments support a claim that Lonergan's perspective is well suited to guide nurse researchers participating on cross-disciplinary health research teams.