sense-data as the best hypothesis

main aim

to argue that the existence of sense-data is the best explanation of illusions and hallucinations

premise one

when we perceive something with property F there is something that is F

premise two

in an illusion or hallucination, the object does not have the property F

conclusion one

so what has the property F must be something mental, a sense-datum

conclusion two

so in illusions and hallucinations sense-data are the immediate objects of perception

premise three

illusions and hallucinations are subjectively indistinguishable from veridical perception

conclusion three

so the immediate objects of perception are the same thing in illusions and hallucinations and in veridical perception

conclusion four

so the immediate objects of perception are always sense-data

development

the logic is abductive, because illusions and hallucinations are subjectively indistinguishable from veridical perception, the best explanation is that the immediate objects of perception are the same