Definition of "percipient"

Fasting, yet not of wantPercipient, he on that mysterious steedHad reach’d his resting-place,For expectation kept his nature up.

1801, Robert Southey, “The Sixth Book”, in Thalaba the Destroyer, volume II, London: […] [F]or T[homas] N[orton] Longman and O[wen] Rees, […], by Biggs and Cottle, […], page 8

[...] he calls attention to the use of glasses [...] The eye itself is no more percipient than the glass; is quite as much the instrument of the true self, and also as foreign to the true self, as the glass is.

1874, John Tyndall, Advancement of Science: The Inaugural Address of Prof. John Tyndall ... Delivered Before the British Association for the Advancement of Science, at Belfast, August 19, 1874‎, New York: Asa K. Butts & Co., page 43

As anatomy, physiology and, later, psychology have developed into more or less well-organized sciences, they have necessarily and rightly come to incorporate the study of, among other things, the structures, mechanisms, and functionings of animal and human bodies qua percipient.

1954: Gilbert Ryle, Dilemmas: The Tarner Lectures, 1953, dilemma vii: Perception, page 99 (The Syndics of the Cambridge University Press)