Answer:
People still don’t understand how the world works.
Step-by-step explanation:
The main idea that this passage wants to convey is that people still do not understand how the world works. This is shown by the fact that people disagree on the fundamentals of science. The author tells us that, while some people (Cartesians) hold a particular opinion, another group (Newtonians) disagree and interpret the world differently. The fact that such different opinions exist supports the idea that we are still learning about the way in which the world works.