The Existence of Existence Among Other Things

"I think, therefor I am." René Descartes stated that he knew that he existed due to the fact that he had thoughts. How then, could he know that the people around him existed? Couldn't it be feasible to argue that if there is no proof that someone else has thoughts (i.e., if you can't experience their thoughts, how do you know those thoughts exist), then how do we know that those around us exist?
We cannot know that something exists unless we experience it. So how could he know the rest of the world around him existed? To say that experiencing existence comes down to just looking aro…