Third doubt is the tool by which we fine tune belief. By stepping back and questioning the truth value of a proposition, we have the opportunity to identify confirmatory and/or contradictory evidence for additional reasoning. If we start with 10 consecutive black balls randomly pulled from a closed box, we may believe the rest are black as well, but if we draw out another ten we are more confident of our findings, and if we examine them all we are assured. This applies as well to our biased opinions of people; one of the great lessons of life is that each human being must be judged individually.
Fourth science offers a reasonable foundationalism for understanding and manipulating the physical world, but subjectivity is more trustworthy, or perhaps unavoidable, for personal understanding and action. Objective and subjective truth are not only different, but to some extent mutually exclusive. Science, not intuition , tells us why the moon does not fall to the Earth like an apple, but internal reflection informs one’s knowledge of good and evil.
Fifth, with care, we can design a practical method to justify beliefs by gauging our degree of confidence in them and then employing a comparative tabulation to guide action in a world of admitted uncertainty. Nonetheless, such a table will require amendments as further reflection, experience, and evidence are processed.
In closing we have learned that our goal cannot be absolute truth, but rather sufficient confidence for ethical action in our lives. The truth value of statements can be evaluated from the standpoint of correspondence with reality, coherence with other principles and observations, pragmatic confirmations, and disciplined contemplation. In the end, certainty is not possible, nor, we hope, essential for a meaningful life.