In short, he was a man of wide talent who moved in the most progressive circles of his time. Like many thinkers of his day, Godwin believed that one could not really ever know the essence of things, for we must always depend upon our own sensations for our knowledge. Consequently, our knowledge will always be limited, and there can be no absolute truths. Despite the fact that all knowledge is only probable, not certain, indeed, because that is the case, we must rely on reason in order to insure that our predictions will have the greatest probability of being correct. He notes that the greater the care taken in the exercise of reason, and the wider the evidence used in that exercise, the greater will be our ability to explain and predict our experience.
All knowledge is built up out of experience through impressions, memory and association.
This moves him into a stream of thought fundamentally different from the Lockeian epistemology, and more in keeping with the Kantian philosophy and 20th century psychology associated with Jean Piaget. To Godwin, like Piaget, the mind takes an active role in organizing experience. Indeed, the mind organizes experience such that conceptions conform to certain laws. For Godwin, these were the laws of association, but these associations are different from those in Locke's view. There are innate processes of understanding associated with reason which allow us to make sense of the world.