4. 1) We should be philosophical skeptics because we have no idea if we have a complete understanding of anything in this world so it is best to doubt everything. For example when the common belief was that the world was flat and all of the planets revolved around the Earth it was the doubters that proved those beliefs to be wrong. The doubters help find new ways to do things like the Wright brothers finding a new way of transportation with planes. Almost no one believed anything would be able to fly that transported humans, and the idea of aviation was nonsense. Skeptics question everything and because of that skeptics find better solutions to problems.
2) We can claim to have knowledge of math, physics, biology, chemistry, genetics, and other sciences but we only know how to apply them to our uses. We do not know why sciences work in the way they do, we just find correlations science has with real life. We have knowledge of math because of mathematical proofs.
We can also claim knowledge of our personal experiences. We claim knowledge of what goes on in our own experiences because no one else has the exact same personal experiences with the same exact same feelings. Even