27652
Based on Gödel 's theorem , it is just not known & ndash ; and never can be & ndash ; if there are " no " paradoxes at all in these theories or in any first-order set theory .
 Gödel
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Gödel