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Many scientific realists ( e.g. , Ernan McMullin , Richard Boyd ) think the operational success of a theory lends credence to the idea that its more unobservable aspects exist , because they were how the theory reasoned its predictions .
 person: Ernan McMullin; person: Richard Boyd
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 person: Ernan McMullin; person: Richard Boyd