phe·nom·e·nal·ism (fĭ-nŏm'ə-nə-lĭz'əm) n.
Philosophy The doctrine, set forth by David Hume and his successors, that percepts and concepts constitute the sole objects of knowledge, with the objects of perception and the nature of the mind itself remaining unknowable. phe·nom'e·nal·ist n., phe·nom'e·nal·is'tic adj., phe·nom'e·nal·is'ti·cal·ly adv.