Final answer:
The two subjects for comparison are men and machines, emphasizing the similarities and contrasts in functionality, purpose and the philosophical implications of such perspectives.
Step-by-step explanation:
The two subjects for comparison in the question are men and machines. the reference material suggests a comparison between the complex workings of the human body and mechanical devices, illustrating how every part has a specific function, yet together they serve a broader purpose.
Similarly, the excerpts provided explore the notion of human beings and their characteristics, capacities, or roles compared to the functionalities of machines. This theme brings up ethical, philosophical, and practical implications of viewing human life and the body through the lens of mechanical efficiency and purpose.