Phenomenalism In epistemology and the philosophy of perception, phenomenalism is the view that physical objects do not exist as things in themselves but only as perceptual phenomena or sensory stimuli (e.g. redness, hardness, softness, sweetness, etc.) situated in time and in space.epistemologyphilosophy of perceptionphenomena In particular, phenomenalism reduces talk about physical objects in the external world to talk about bundles of sense-data.