Rationalisme et objectivisme

Question: How does Objectivism differ from 18th century Rationalism?

Answer: On the general level, Objectivism and Rationalism differ because the former is a philosophical system encompassing metaphysics, epistemology, ethics, and politics. Rationalism is a particular epistemological viewpoint, and not a system.

So how does the Objectivist Epistemology differ from Rationalism?

Rationalism in its strongest form is the position that reason is the only means by which to acquire knowledge. It is usually contrasted with empiricism, the view that our senses are the primary means of knowledge.

The most famous Rationalists were Descartes, Spinoza, and Leibniz. While their respective philosophic systems were different, they did share the view that the truth is accessible only by use of our reason, and that this process doesn’t involve the use of perceptual data. Knowledge acquired through the use of reason is more certain and reliable, while the senses are at best inadequate, and at worst deceptive.

According to Rationalists, knowledge is acquired by finding principles that can be known directly by reason, and then by deriving all other knowledge from these principles. For example, Descartes’ principle of "I think, therefore I am," is the starting point for all knowledge in his philosophic system.

The problem with rationalism, simply put, is that it tends to leave out the facts. Reality is complex and facts have many aspects that one must consider to form knowledge. Thus Descartes’ physics, built on rationalistic assumptions about motion, is wildly wrong, while Newton’s physics, derived according to the motto "I don’t hypothesize [in the absence of facts]," is essentially true and remains part of the scientific canon to this day.

Objectivist epistemology is not a form of Rationalism because Objectivism holds that all knowledge is derived from and validated by perception. Perception, according to Objectivism, is veridical; it does not deceive us. In fact, perception is the only form of awareness of reality there is, and therefore, it is the only source for knowledge. (For more on the validity of the senses, see David Kelley’s Evidence of The Senses.) So in contrast to the Rationalists, Objectivists do not hold that knowledge of the world can be directly known merely through the use of reason.

On the other hand, it is not completely accurate to call Objectivism a kind of empiricism. In the most general sense of the term, as the view that our senses are the primary means of knowledge, Objectivism is a kind of empiricism. However, the Objectivist theory of knowledge differs substantially from prominent empiricists like John Locke and David Hume, and so calling Objectivism a kind of empiricism might be confusing.

According to Objectivism, reason plays an essential role in forming and developing our knowledge. While the senses are the source for all knowledge, reason integrates all our perceptual data into concepts and principles. In this way, Objectivism begins to look less like a theory of empiricism.

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