Tag Archives: Aristotle

In Defense of Self Evidence

A self evident proposition is a proposition that any rational person will agree is certainly true upon grasping it. In this post, I will demonstrate that there are self evident propositions.

The strongest argument for the claim that there are self evident propositions is to just list several of them so that the reader can see that some propositions are really self evident. Here are three:

  • There is an objective reality.
  • A thing is identical to itself.
  • I am conscious.

I will explain each of these.

“There is an objective reality” means that there is a fact of the matter about something. For example, if I say that we landed on the Moon, and someone else denies that we landed on the Moon, there is a fact of the matter about which of us is right. The fact of the matter about whether we landed on the Moon is one component of the objective reality in which we live.

The existence of an objective reality is contained in every experience we have. When I experience the fact that my alarm clock is red, I can see immediately that my alarm clock really exists, that it really has certain properties like redness, and that its existence and properties are independent of my mind. This experience shows me directly that there is an objective reality.

“A thing is identical to itself” means that a thing is what it is. A tree is a tree, and has all of the properties required for being a tree. Symbolically, this is often expressed “A is A,” where A refers to anything that exists.

This proposition, called the law of identity, is contained in every thought and every observation we have. When you observe a computer, you also observe that that computer is a computer. When you think of the number one, you can see that the number one is the number one. This is one of the undeniable foundations of rational thought.

“I am conscious” means that I am aware of the world and can identify things that exist using my mind. I can perceive the things that exist, whether they be cars, animals, or anything else that is presented to my senses. I am actually aware of the world.

Obviously, the fact that we are conscious is forced upon us by every perception or thought we have. If I perceive a lamp, I can see that I am aware of that lamp. If I think about Nazi Germany, I can see that my mind is thinking about Nazi Germany. Every act of my consciousness contains consciousness. Thought and perception are undeniable data of experience.


Having gone through these examples of self evident propositions, we can see that there are in fact self evident propositions, since there can be no doubt about the existence of an objective reality, the law of identity, or consciousness.

Some philosophers have raised objections to the idea of the self evident, and I may address those objections in another post. Keep in mind, though, that even if we do not know the answer to some tricky objection, that casts no doubt on the idea of self evidence or the self evident propositions I have enumerated. We can see, just by looking at them, that any objection to these propositions has to fail, even if we cannot identify the error in a specific objection.

My Objections to Hume

I posted the following in response to a request for my thoughts on Hume:

My main two objections to Hume are his view of induction and his view of morality.

I don’t agree that inductive inferences are merely a matter of habit – we do perceive causality, although we perceive it originally in specific instances and then abstract the concept of causality from those instances. Causality isn’t immediately perceivable like the color red is, but we can learn of its existence by inference from things like pushing a ball and watching it roll, and scientific theories are broader generalizations induced from numerous directly perceivable causal connections like this.

I also don’t agree that morality is a matter of the sentiments rather than of relationships between things. We do originally become aware of moral distinctions by means of the sentiments – I don’t like being hurt, so I conclude that that’s bad, and I like having friends, so I conclude that that’s good. However, there is an objective moral standard that we can infer from these primitive moral beliefs, based on a specific kind of life that it is best for a human being to have, one centered on our own self interest.

So basically, I think Aristotle has better positions on these issues than Hume does. I might do a longer post on Hume later.