<P> Weak versions of behaviorism in psychology admit the existence of mental phenomena but not their meaningful study as causes of observable behavior and view mental phenomena as either epiphenomena or linguistic summaries, instruments to examine objectively observable physical behavior . </P> <P> In the field of complex systems, the term epiphenomenon tends to be used interchangeably with "emergent effect". </P> <P> Zenon Pylyshyn suggested a propositional model of cognition where people do not conceptualize ideas in images but rather in meaningful relationships . In this theory, epiphenomena refer to images because they are merely products people conceptualize from their actual thought processes . Pylyshyn defends his claim by explaining that we only see images when we envision the form of an object . While visualizing objects or actions is a frequent process in our mind, it does not occur when we are considering the meaning behind an action or the non-visual properties of an object . There are many concepts we simply cannot envision . Additionally, when envisioning an image, it changes based on our preconceived notions, suggesting that semantic relations precede visual images . Unfortunately, the idea of epiphenomena in propositional theory is largely subjective and not falsifiable . </P>

Who argued that imagery might be an epiphenomenon