Debates about physicalism are sometimes hampered because participants can't seem to agree what "physical" is. I'd like to invite all physicalists and those who believe they are clear about what physicalness is to create an exact definition. I'll offer my opinion first. I think physicalness is mass, immediate effects of mass, and all that which has come about from the presence of mass. Since all mass we know of is believed to have originated with the Big Bang, then I'd also restrict the definition of physical to how mass and mass effects have developed from that event. In a past thread I posted the following in support of my definition: Princeton's Word Reference site give the definition of physical science here: - the science of matter and energy and their interactions On the same page you can find a definition for physicalness: - the quality of being physical; consisting of matter The Word Reference site gives several relevant definitions of physical here: 1* physical - involving the body as distinguished from the mind or spirit . . . 2* physical - relating to the sciences dealing with matter and energy; especially physics; "physical sciences"; "physical laws" 3* physical, tangible, touchable - having substance or material existence; perceptible to the senses; "a physical manifestation"; "surrounded by tangible objects" 4* physical - according with material things or natural laws (other than those peculiar to living matter); "a reflex response to physical stimuli" 6* physical - concerned with material things; "physical properties"; "the physical characteristics of the earth"; "the physical size of a computer" Of Physicalism the Wikipedia says: Physicalism is the metaphysical position that everything is physical; that is, that there are no kinds of things other than physical things. Likewise, physicalism about the mental is a position in philosophy of mind which holds that the mind is a physical thing in some sense. This position is also called "materialism", but the term "physicalism" is preferable because it does not have any misleading connotations, and because it carries an emphasis on the physical, meaning whatever is described ultimately by physics -- that is, matter and energy.