I began this thread regarding witnessing to atheists by discussing a logical train of thought rather than the Bible. I opined that reality is interconnected or unified, so that it is not necessary to worry about where to start exploring, but I began like Descartes by asking whether there is some truth which is not debatable--which everyone believes at least implicitly and uses as a common point of departure in discussing ultimate reality?
I proposed that there is such axiomatic truth, because in order to study reality it appears that one must (logically or implicitly) begin by assuming at least the reality of the student, so that absolute skepticism in philosophy is like absolute zero in physics: it serves as a hypothetical point that is not actually achieved or else nothing would happen. However, I acknowledged that skepticism does serve to admit the truth that finite human beings cannot know absolutely, infallibly, perfectly or objectively. This truth was expressed by the apostle Paul in the New Testament (NT) book of 1 Corinthians 13:9&12, “We know in part . . . We see but a poor reflection” (as in a fogged mirror).
Partial knowledge or uncertainty does not prevent would-be skeptics from talking as if knowledge with some degree of confidence were possible the moment they attempt to communicate their doubts. An agnostic assumes at least implicitly that truth is believable, rational and meaningful, even though unprovable or subjective. These three affirmations seem to be a priori truth or unavoidable (beginning) beliefs: 1. Truth or reality exists (cf. EX 3:14, God is “I am” or the essence of existence), 2. (Objective) reality is subjectively known by seekers (cf. 2 CR 5:7, “We live by faith, not by sight” or proof), and 3. Reality is meaningful and communicable or able to be discussed rationally in fellowship with other truthseekers (cf. IS 1:18a, “Come now, let us reason together.”).
That is how I began, but I would like for y'all to share how you like to begin witnessing to atheists.