Other forms of epistemological pluralist dualism include psychophysical parallelism and epiphenomenalism. Jackson himself went on to reject epiphenomenalism, and dualism altogether. However, epiphenomenalism flourished primarily as it found a niche among methodological or scientific behaviorism. For example, Victor Argonov states that epiphenomenalism is a questionable, but experimentally falsifiable theory. This contradicts epiphenomenalism because it involves a conscious state causing an overt speech behavior. However, Argonov suggests that experiments could refute epiphenomenalism. A large body of neurophysiological data seems to support epiphenomenalism. This is the sense that is related to the noun "epiphenomenalism". According to epiphenomenalism, animals experience pain only as a result of neurophysiology. Later, however, he rejected epiphenomenalism. Some thinkers draw distinctions between different varieties of epiphenomenalism.