Self-Evident vs. Obvious

The terms "self-evident" and "obvious" might seem interchangeable, but they actually describe very different kinds of truths. For example, if you’ve learned basic arithmetic, it’s obvious that two plus two equals four. However, this truth isn’t self-evident; it’s derived through a process of counting and comparison. On the other hand, the fact that you exist with consciousness, and are reading this text, doesn’t require any inference—it’s self-evident.

Sensory perception provides us with self-evident data. When you see, hear, or touch something, the existence of those percepts is self-evident. However, the meanings we derive from these perceptions, and the inferences we draw, are not self-evident. These interpretations need to be validated by tracing them back to the self-evident data provided by our senses.

Critics of the concept of self-evidency often argue that past beliefs, like the medieval view that the world is flat, were considered self-evident but were later proven wrong. However, this misunderstanding arises from conflating what is actually given in perception with broader inferences or assumptions. Medieval people perceived a small part of the Earth’s surface, which appeared flat within the limits of human vision. The idea that the entire Earth was flat was an inference or assumption, not a self-evident truth. Today, astronauts can see the Earth's round shape directly from space, making it self-evident to them.

Another example involves the Earth’s revolution around the sun. It isn’t self-evident that the Earth orbits the sun or vice versa. What’s self-evident is the relative motion between the Earth and the sun. Determining which celestial body orbits which involves scientific reasoning and isn’t something immediately self-evident. These supposed counterexamples don’t undermine the concept of self-evidency. The statement “Existence exists” is a self-evident fact, one that we confront in every waking moment, from our very first acts of awareness to our last. Unlike more complex truths, which require proof, the existence of existence doesn’t need to be proved—it’s directly percieved and undeniably evident.

Although the truth of “Existence exists” does not have to be proved, one does have to prove that, within the class of truths, it has the special status of an axiom.