People can deny a lot of science without making a huge difference in their lives; no one will die if they deny evolution. Gravity, on the other hand, will kill you. You can't just jump off a building and deny it exists and expect a positive outcome.
This unseen force dominates our entire lives so completely we forget it exists. We drop pencils and struggle to walk uphill and go on with our lives.
How people account for this invisible influence while moving through the world
was the subject of a recent experiment, and the results showed we regard it a lot differently when we can see it instead of feeling it through changes in weight and balance.