"But the fact a person denies that he is theorising is no reason for taking him at his word and failing to investigate what implicit theory is involved in his statements"

This quote by Talcott Parsons is emphasizing the importance of understanding the implicit theories that are present in a person's statements, even if they deny that they are theorizing. He is suggesting that we should not take a person's word for it and instead investigate what implicit theories are present in their statements. This is important because implicit theories can often be more influential than explicit theories, and can shape the way we think and act. By understanding the implicit theories present in a person's statements, we can gain a better understanding of their beliefs and motivations. This can help us to better understand their behavior and make more informed decisions.