While Descartes believes that knowledge can be gained by reason alone, Hume’s Empiricism suggests that we can only gain knowledge from the experiences of perceptions, which he called “Impressions.” Rationalists use skepticism to find the most clear and distinct truths and build their foundations from there. Ultimately, Descartes states there are 3 substances that exist- God, mind and body. From doubt and confusion, Descartes finds clarity. Empiricists on the other hand, reject rationalism suggesting knowledge that can not be traced back to an impression from the outside world does not have any meaning. Hume also believes that there is no causality in the world, therefore we can never gain knowledge from events that we have witnessed in the past or the future. Unlike Descartes, how starts in skepticism and ends in clarity, Hume starts with a strong view of how our minds collect raw sense data and ends in skepticism. I argue that Hume's philosophy is more practical because it relies on the senses.
Both philosophies were born from the rise of the Scientific Revolution.
According to Descartes, to gain true knowledge, you must first doubt everything. When you reach the point at which you cannot doubt anymore, you achieve the foundation of knowledge. When you doubt everything, you realize that the only thing you cannot doubt is that you are a doubting thing; therefore you must exist in some way. From there, you can reason that there is a more perfect being that exists because you are not perfect if you doubt, and you have an idea what a perfect being is. This perfect being is God. God is also a good being because
Descartes calls these truths, these clear and distinct perceptions. From reason alone, we can affirm the existence of God, Mind and the Body.