"I think, therefor I am." RenÃÂ© 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 around at the world, then wouldn't it be valid to say that we only exist in our minds? The world is made up of interpretations by the electrical and chemical impulses that make up the brain. So, couldn't it be possible to argue that no one truly knows that the world exists?
If the world is made up by these interpretations, then how can one not argue the same about dreaming.
Dreaming is made up by imagined situations and places while a person sleeps. In dreams, a person can experience taste, sight, smell, touch, and hearing, just like the physical world. If our dreams are made up of the same substances that our so-called waking world is made up of, then there is only one difference between the two worlds; we can awake from dreaming. So then, one could easily argue that that's how we as humans know exactly what reality is. Perhaps though, there is a way for humans to awake from reality.
No one is quite sure what happens when a person dies. We know that the heart, lungs, and brain stop working. We know that we turn cold and decay.