This essay argues for the value of presence as rhetorical heuristic. Beginning with the philosophical tradition, the authors establish a long-standing interest in presence or isness, understood as the thing-itself outside subjectivity. We then trace how rhetorical theorists including Aristotle, Quintilian, and Perelman have privileged isness as a baseline for true conviction, positioning rhetoric as an effort to imitate material proofs. Such views highlight the tension between presence (things of the world in their isness) and the arts of presencing (the capacity of words and symbols to shape an isness), suggesting a generative frame for analysis. To demonstrate, we examine global migration. Drawing on ethnographic fieldwork among undocumented migrants, we posit that these individuals' paradoxical experiences of bodily presence but legal absence reveal a fraught interplay among rhetoric, state power, and competing notions of truth. However, immigration is only a case study; presence is a much more widely applicable heuristic.