In essence, there is only one philosophical mistake: to accept an arbitrary rather than an objective standard.
Arbitrary means “making a claim in the absence of evidence.” An arbitrary idea is one that is not connected to any particular observed facts. Arbitrary ideas are worse than false ones, for they make no attempt at knowledge and they divert the mind away from any process of knowledge.
There are four main ways to make the mistake of admitting the arbitrary: It may enter into our idea of what is true, what is good, what is right, and what is just. These are four philosophic fields. They correspond to metaphysics/epistemology, value, virtue, and social relationships.
The arbitrary should be rejected in the following manner:
Is faith reasonable? It is. We should reject blind faith and accept reasonable faith. This view excludes whim-worship or mysticism.
Is “good” objective? It is. We should reject the blind acceptance of the value judgments of others. Individuals should identify their own objective values. For an individual, something does not even fully become a value until it is recognized to be. Thus “value” involves both reality and the recognition of it. This view excludes subjectivism or intrinsicism.
Is self-interest always the right motivation? It is. We should reject a morality of duty and self-sacrifice in favor of a morality of rational self-interest in which one always acts for what he understands to be his own long-term benefit. This view excludes collectivism or altruism.
Is God right to judge people? He is. We should reject the view of God as ever-patient, ever-forgiving, and ever self-sacrificing. The biblical picture is that God always seeks his own glory and self-interest. He justly rejects and defeats his enemies. This view excludes egalitarianism or universalism.
Scripture supports an objective view of the true, the good, the right, and the just.
Faith is reasonable. The good is objective. Self-interest is the standard of action. Judgment is morally right. These four categories have implications for our understanding of all aspects of life because they cover the entire realm of philosophy.