This has become the atheist motto at Brandon Vogt’s new digital areopagus, Strange Notions, not an unfair question at all, but one that deserves addressing. It goes like this.
What is “evidence”? Evidence refers to that which is evident, that which is visible, manifest, conspicuous, on display, something serving as observable proof. If something is evident, then it can be determined by anyone (who looks) to be true. If something is not evident, it cannot be publicly verified.
Evidence refers to visible public information.
If it were true (it’s not) that the material world were all that existed, then someone who has a “belief in God” is merely holding an opinion in his brain matter, a delusion. So when they ask for evidence, they are asking for some visible, public object that anyone can see, knowing that God is not going to suddenly appear in physical form before them all to say, “Howdy I’m God!”
But what does science have to say about vision if it’s so critical for evidence? Oddly, science says vision is also a kind of delusion. This is from an essay provided to me by Max Weismann, philosopher and co-founder with Mortimer Adler of the Center for the Study of the Great Ideas. In this essay written by Sir Alfred Brian Pippard and first published in Contemporary Physics in 1988, titled The Invincible Ignorance of Science, he argues that science keeps leading us to more and more questions, every time we think we understand matter, we discover we don’t. I’ve read it numerous times now, and it takes some digesting. Here’s what he said about photons (broken into paragraphs for clarity).
Ever since Planck and Einstein, at the beginning of the century, we have lived with the idea of the photon as the quantum of light. To physicists and anyone concerned with photochemical processes the photon is as real a particle as the electron, and nobody questions the propriety of the concept of quantum efficiency applied to optical detectors.
The quantum efficiency of a single rod in the retina is close to unity—only one photon is needed to initiate a chemical process whose ultimate outcome can in principle be a nerve impulse to the brain.
Let us suppose, as is not technically possible, that a single atom is held isolated in a vacuum, and stimulated so that from time to time it emits a single photon, and that we sit watching for these photons as they emerge. According to standard theory, at every emission process the atom is to be imagined radiating an electromagnetic wave which spreads in all directions; the intensity of the wave that is focused on to a rod receptor in one of my eyes determines the probability that the photon will turn up there rather than outside the eye. But what about my other eye, or for that matter one of your eyes if you are also sitting there waiting for an event?
The wave reaches rods in every eye, yet there is only one photon available to stimulate a response. If I see a photon, how does your eye know that there is no photon for it, even though the wave is just as strong as it was for me? If we could believe that the atom emitted a real photon in one particular direction, and that the wave simply served to make some directions more likely than others, we should accept the uniqueness of the response without question.
But it is precisely this escape route which is firmly blocked by von Neumann’s hidden-variables theorem. Thus the only intuitively reasonable explanation is disallowed, while the unreasonable explanation provided by quantum mechanics yields the required answer without difficulty. We have to lump together into one grand Schrödinger equation the radiating atom and all the receptors that might be excited, and it then emerges that for every atomic process at most one receptor will record a stimulus.
In simpler words, we don’t know what photons are. We have mathematical models to explain appearances, but photons ultimately defy comprehension. The full document is here. I think I’d like to cover it in more depth next week.
My doctoral research focused, in part, on simulating photosynthesis and I had to use equations to measure the quantum yield of photons doing their thing on nano-composite materials. I had to place a great deal of faith in the equations people who lived before me derived, and I had to trust that they could adequately describe and predict experiments. My specimens looked like a glop of sand but instrumentation told me they had sophisticated photosynthetic polymers and inorganic monolayer crystalline sheets layered on them. I used a LASER beam, optically amplified light from the stimulated emission of electromagnetic radiation, but all I saw was a box with a lot of dials and an intense beam coming from it. I saw signals from Fourier-transformed time-resolved luminescence equipment, data on paper that told me to celebrate, or the other 99% of the time, to change something and try again. I never saw the artificial photosynthesis systems working directly.
To be a chemist is very much to operate in a realm of the invisible. People have asked me before how a scientist could become a Christian, believing in a God whom we cannot see. How could I find it possible to arrive at truth without visible evidence laid before me?
Maybe they don’t realize how little we understand about the light striking our own eyes. Saying we see light is not altogether different from saying we see God, but even light will elude our eyes if we squeeze them shut hard enough.