Descartes wasn't the only thinker in the early modern era. There were many who thought that it was important to start from the physical world. Francis Bacon, for example, constructed a scientific method around observation and categorization of the aspects of the physical world.
But it was up to John Locke to initiate the movement later known as empiricism. Empiricists believed that none of our knowledge came from the mind by itself. It was all from sensation about the world. That meant that the mind was dependant on that world.
Locke set out to trace our knowledge from the earliest simple sensations to the most abstract and general ideas we have, about things like freedom, justice, and so forth.
For more details on how Locke builds up this knowledge from simple to complex, go to this link.