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The founders of quantum mechanics debated the role of the observer , and of them , Wolfgang Pauli and Werner Heisenberg believed that it was the observer that produced collapse .
 Wolfgang Pauli, Werner Heisenberg
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Wolfgang Pauli, Werner Heisenberg