Rationalism is the belief that reason is the best or most reliable way to gain knowledge. It is often contrasted with empiricism, which emphasizes the role of experience and observation. There are different forms of rationalism, but all share the idea that reason is a powerful tool that can be used to gain knowledge about the world. Reason can be used to analyze data, make deductions, and reach conclusions. Rationalists believe that knowledge is primarily gained through reason, rather than experience. There are many different philosophical arguments for rationalism. One of the most famous is the argument from first principles, which states that certain truths (such as the existence of God or the laws of logic) can be known without needing to observe the world. Other arguments for rationalism include the idea that reason is the only faculty that can give us certain knowledge, and that it is more reliable than sense-perception. Rationalism has been very influential in the history of philosophy, and has shaped the thought of many famous philosophers, including René Descartes, Baruch Spinoza, Gottfried Leibniz, and Immanuel Kant.