Is it possible that there are physics that we will never discover because our limited biological senses?
Answer - Not so much biological senses as we can build better equipment to increase the range but there are likely order of magnitude restrictions as we approach the extremes of the micro and macro world - Planck Time and Planck Length for example. We are already aware of the various innate limitations associated with Heisenberg’s Uncertainty Principle.
Why did earlier scientists not guess about the gravitational force?
Many of them knew about it they just talked about it in different terms - such as a natural attractor. Newton’s greatest breakthrough in this area was not so much gravity itself but the universal notion of gravity, or his realization that the same force responsible for the terrestrial phenomena acts as well in the celestial sphere and is key to our understanding of planetary/lunar motion.
If the Philosophers' Football Match from Monty Python actually took place, would the Greeks beat the Germans?
No because the Germans cheated and included Beckenbauer in their line up.