Apart from the formal philosophical definition of ‘certainty’, for most people, the word means ‘firm conviction that something is the case’.
If we were not reasonably certain of most things then we would be incapacitated and unable to perform daily functions. For example, if I were not certain that gravity would hold me onto planet earth, I would walk around in perpetual fear or anchored to a peg in the ground. Our conviction that some things are certain enables us to function, make life decisions, and teach others. But, on what basis do we establish certainty?
Recently, I have been discussing reincarnation and life-between-lives with someone who is, himself, in dialogue with a person who believes in these things. This 3rd person is certain enough about them that he is prepared to stake eternity on them and to endorse them to others. What is his basis for certainty?
Many, particularly those of my generation (and I am 70), base certainty on authoritative statements. Something is certain because some authoritative person, organisation, or document states that it is certain. For traditional Roman Catholics, their church is authoritative, for Evangelicals the Bible is authoritative, and so on.
Agnostics or atheists also appeal to authorities ranging from the opinion of experts, to generally accepted scientific theories. They also rely on logical reasoning and empirical evidence. For them, something becomes certain if, say, Stephen Hawkins said it was, or it makes logical sense, or if there is hard factual evidence for it.
For post-modern and millennial individuals, nothing is certain, however, they regard group consensus, the opinions of social media thought leaders and personal preference as reliable enough to provide sufficient certainty to function normally.
I return to the man who is certain that we all live many times on earth: He believes that between the many live-times on earth there is a complex system of personal development and that neither God nor evil exists. Why is he certain of these things? Firstly, because he has read two books by someone who claims to have hypnotically regressed thousands of patients to a point where they can recall their previous states of being. Secondly, because it lines up with what he believes to be reasonable, and thirdly because it is what he wants to believe.
Contrary to this approach, my basis for certainty lies in one person as revealed in one authoritative document – the Lord Jesus Christ as revealed in the Bible. 2 Peter 1:16-21 provides a compact presentation of why I hold to this.
‘We did not follow cleverly invented stories when we told you about the power and coming of our Lord Jesus Christ, but we were eyewitnesses of his majesty. For he received honour and glory from God the Father when the voice came to him from the Majestic Glory, saying, “This is my Son, whom I love; with him I am well pleased.” We ourselves heard this voice that came from heaven when we were with him on the sacred mountain. And we have the word of the prophets made more certain, and you will do well to pay attention to it, as to a light shining in a dark place, until the day dawns and the morning star rises in your hearts. Above all, you must understand that no prophecy of Scripture came about by the prophet’s own interpretation. For prophecy never had its origin in the will of man, but men spoke from God as they were carried along by the Holy Spirit’.
The basis for my certainty in things eternal does not come from any so-called experts, or cleverly invented stories. It comes from the divinely authenticated witness to The Lord Jesus in and through a Holy Spirit illuminated understanding of the scriptures. In addition, I have subjected this revelation to rigorous logic, factual evidence, and personal experience.