بسم الله الرحمن الرحيم
Despite the repeated use of the phrase “there is no proof or evidence for the existence of God,” I would imagine most atheists, and indeed most people, are unaware that there is in fact a technical difference between evidence and proof. Fittingly, the distinction between proof and evidence was initially taught to me in an introductory evolutionary biology course by an ardent atheist professor during my first year of university. My professor used this distinction to justify why she would not be receiving objections to evolution in her class. (Literally, she said that we were not allowed to question evolution or present counter evidence during the lecture, and that she would not entertain it during her office hours.) It was the most bizarre and dogmatic moment I had in my entire education, and I say this as someone who was blessed to study theology in a seminary environment for a year. Contrary to popular opinion, the seminaries are far less dogmatic when it comes to foundational beliefs, as they permit questioning the existence of God and raising objections to the proofs offered.
She argued that evolution was based upon good evidence, but could never attain the status of complete certainty. It was a probabilistic argument, like virtually all of science, rather than a demonstration, as in the case of mathematical proofs (and, as we shall see, metaphysical arguments.) I still vividly remember the slide used to showcase an example of rational certainty – it was that of a triangle with some lines and an accompanying trigonometric proof.
Because evolution (along with all empirical science) could never attain 100% rational certainty, she argued that it was always possible to be a skeptic, to raise objections about inductive inferences which are probabilistic at best, or to posit alternative explanations that could explain the data, no matter how improbable. Oh the irony. If scientific atheists only applied their standards consistently, they would either deny science or accept God. We will see why more clearly later on when we explore the evidence for the existence of God. But that is neither here nor there. For now, what I want to do is just go over some basic concepts in reason in order to set the table for the coming arguments.
Reasoning is divided into two parts; inductive and deductive. As we shall see, inductive reasoning depends on deductive reasoning, which is higher in the hierarchy we are in the process of building. Inductive reasoning works by evaluating the probability that one thing is true, given another set of truths. Deductive reasoning works by understanding that some things are necessarily true, given another set of truths. “Evidence” pertains to inductive reasoning. “The evidence” is the set of premises or supposed truths on the basis of which we make a probabilistic judgement. “Proof” pertains to deductive reasoning – it refers to the premises which if true, show a conclusion to be necessarily true as well (or proven). This is the process upon which all of mathematics are built.