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Empiricists , like David Hume , had argued that all realities in the outside world are products of human sense perception , thus all realities are merely perceived : they do not exist independently of our perceptions , and have no causal power in themselves .
 person: David Hume
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: David Hume