Answer: a.sensory evidence the foundation of knowledge
Descartes believed that we can access knowledge through our senses. This is the way we experience the world. However, he argued that our "humanity" was our ability to perceive things and reflect on them. This is why humans can know they are real: because they can perceive things and think about them. Perception and rationality go hand in hand.
The idea of sensory evidence is present in Galileo's thought as well. He similarly believed that senses needed to be paired up with rationality, as they can deceive us sometimes. For example, we might perceive the Sun to be moving even though it is the Earth which is in fact in motion. Nevertheless, Galileo recognized the importance of our senses in gathering data about the world.
