Rationalism – The Decision Lab

Along with Empiricism, which stresses the use of sense perception rather than pure reason, Rationalism was one of the primary streams of intellectual thought during the Enlightenment period a cultural movement spanning the seventeenth and eighteenth centuries. A focal debate of the Enlightenment was its controversy around the power of reason; most philosophers at the time praised the power of reason, but argued that the source of knowledge must be sensory experience.11

Rene Descartes ideology challenged this proposition; he argued that the knowledge of eternal truths could actually be attained by reason alone, without the need for any sensory experience. His famed proclamation of existenceI think, therefore I am defines this very reasoning; it is a conclusion reached by reasoning alone and not inferred through experience.12

The rationalist position was that knowledge isa priori(from earlier something you already have when you think about it). It is something that is reasoned out, for example, through the processes of mathematics or logic. The human mind is equipped with rational faculties, and if we utilize them, we can reach the truth. Reason, operating within the laws of logic, can attain knowledge of truths that owe nothing to sense experience.13

Descartes methodology was later adopted by Wilhelm Leibniz and Benedict Espinoza, two important figures in the development of Rationalist thought. Both agreed that the framework of knowledge could be known bya priorithinking. But the difference was their point of origin: Spinozas point of origin was not the self, but with that of the universe or God which he named Substancean independent entity that needs nothing else to be conceived or exist. From the idea of Substance, Spinoza derived his entire system, contending that all aspects of the natural world and humanity were modes of this eternal Substance, and can therefore only be known through pure reason.14

Meanwhile, Leibniz expanded on the idea that principles can be accessed by reason alone with his idea of innate knowledge. He proposed that something like mathematical truths are not revealed by the senses, but rather, it isreasonthat allows us to procure universal truths from individual instances. Therefore, the mind is the source, which means such truths exist innately.15

While Descartes, Spinoza, and Leibniz are championed as the groundwork-layers of the 18th-century Enlightenment, Immanuel Kant, another prominent Rationalist thinker, came into the foreground during this period of intellectual excellence. Kant emerged to synthesize the relationships between human experience and reason, and attempted to put an end to an era of speculative theories of human experience. He did so by pointing out the flaws in both the Empiricist and Rationalist schools of thought.

Kant argued there were deep-seated problems with Rationalism. Pure reason, asserted Kant, is flawed when it goes beyond its limits and makes assertions on things that are beyond the realm of all possible experiencethings like the existence of God, or the idea of free will. Regarding empiricism, Kant affirmed the necessity of experience for human knowledge, but suggested that reason is equally necessary for processing that experience into coherent thought. He concluded that both reason and experience are necessary for human knowledge, and called his framework Transcendental Idealism.16

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Rationalism - The Decision Lab