92491
The term " Darwinism " was used for the evolutionary ideas of others , including Spencer 's " survival of the fittest " as free-market progress , and Ernst Haeckel 's polygenistic ideas of human development .
 Spencer, Ernst Haeckel
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Spencer, Ernst Haeckel