Question: who argued that class struggles were what led to historical progress and development
[{'answer': 'Mikhail Bakunin', 'provenance': [{'wikipedia_id': '42437083', 'title': 'Class conflict', 'start_paragraph_id': 4, 'start_character': 60, 'end_paragraph_id': 4, 'end_character': 75, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]