Sometimes people disagree over whether or not a truth is self-evident. Some people that the statement is true, but not self-evident. Others believe that the statement is false. In either case, they do not believe that the statement is self-evident. Unless there is a fair and logical way to adjudicate this disagreement, it will not be possible to build a philosophy on top of self-evident truths.
If there is disagreement between two people over whether or not a particular statement is self-evident, mere assertion will not solve the problem. First, we must ensure that both parties mean the same thing when they disagree over the statement. Precision must be used to determine the exact meaning each party is using and ensure that they are completely and utterly identical. If both parties still disagree over the truths, then it is time to move to the next step.
After determining that both parties understand the statement the same way, the party that believes it is self-evident must be able to declare what kind of self-evident truth it is and give evidence of some kind for that. It is not possible to give an argument that a particular self-evident truth is true, but it is possible to explain what kind of self-evident truth it is and what evidence there is that the truth is self-evident. The party that believes that the truth is not self-evident must, at the very least, explain why the evidence is insufficient. They cannot demand a deductive proof, but they must show that the evidence is insufficient to show that the truth is self-evident even if the truth were self-evident. To do otherwise would beg the question against their opponents.
As an example of this, suppose someone said that the existence of God is self-evident. I would disagree. Since both myself and my opponents have the same definition of God, then are then required to explain what kind of self-evident truth it is and what the evidence is. But they might merely claim that God’ s existence is obvious to those who do not willingly refuse to see it. Since that it not evidence, their position is a lost cause. Therefore, God’ s existence is not self-evident.
My example is somewhat contrived because God’ s existence might be self-evident to some but not to all. In that case, and in any case where both parties cannot agree that a particular truth is self-evident after following these steps, the party promoting the self-evident truth must accept that it is not self-evident to their opponents. At best, it is only self-evident to them.
Any further arguments must proceed with other self-evident truths or without the premise that the truth is self-evident.