A few days ago, I had a discussion with a friend who enjoys having informal debates with theists. This is not usually my thing. I find the discussions to be pedestrian on account of theists typically not understanding basic concepts of logic. Their arguments tend to get get muddled and if I can get them to understand that much, it might well be deemed a miracle by the Catholic Church and I could finally become Saint Patrick #2.
I find that inevitably the theist will fall back on glib statements like, "That's just what I believe," or "It's all about Faith." Which tells me there was little point to having the discussion in the first place. I can only hope that this sort of person may eventually come to their senses after reaching a dead end with their belief enough times. Though, in my experience the person just stops talking about such things with me.
Anyway, back to my friend. We'll call him John. John doesn't really have any formal training in logic or science and he tends to shoot from the hip when he argues. Despite this he gets it right most of the time. He calls me after arguing with somebody on Facebook for a few days and since I'm not on Facebook, he has to email me a copy of the thread. After reading it, I send back a response telling him essentially where he went wrong.
In short, John first let the theist get away with comparing faith in a deity with faith in science. Second, he let the theist twist his words about "proof" into "absolute proof" which allowed the theist to create a few subtle strawman arguments. He then portrays John as being disingenuous when John mentions a 95% confidence interval.
These are my words summing up the discussion in brief. John doesn't actually know anything about statistics and 95% confidence intervals. As I was re-reading my response to John, it occurred to me that probably many people don't really have a keen grasp on how such things work in the scientific method and I decided that if I posted that same info here, there is a chance it may benefit someone else. Here is my response to John with some minor adjustments to compensate for this change in venue. I even left in a short personal rant about how the media reports science, sorry for that.
The fact that anyone would say, "This was before we had the premise that 95% confidence can equal proved" shows how little that person understands science. Science cannot "prove" anything if you're goal is absolute certainty. This is why scientists are forever stating margins of error and confidence intervals. Alas, most people lack this understanding, and indeed, when science is reported in the media, the margins are often ignored. Once a reasonable person understands that this is how science works, the question only becomes, to what level of tolerance must something be demonstrated before they are satisfied with the result?
Without getting into a discussion on prospective vs. retrospective vs. other types of studies, I'll simplify things and say that generally a 95% confidence interval for initial data is convincing enough for most scientists to proceed with more studies. For science to be useful as an empirical tool, a phenomenon must be replicable. So more studies are done. Oftentimes, further studies with better control over the variables shows that there was never anything there in the first place and eventually the hypothesis is discarded. Other times, better data, lead to the need for better/bigger studies. One simply follows the evidence.Personal Rant:This is why science reporting in the media is so disheartening. I can't tell you how many times I've read articles about "A scientific study that shows X", only to find out the study was on 55 people. Which means this was a simple prospective study, done to see if further studies should be done. This is tantamount to reporting on a student taking an exam and saying, "This student got 4 out of the first 5 questions correct, so we assume he'll be getting a B." Such lazy reporting is also why you have contradictory news articles about how X is good for you one week, but 6 months later X is bad for you. This happens when a prospective study was overturned. After all, with a 95% confidence interval on initial data we'd expect about 1 in 20 prospective studies to yield the wrong answer. Or worse yet, maybe X is good in one context and bad in another and the context isn't made clear. after all, reporters are more interested in headlines than details.
/RantAnyway, back to the topic of what constitutes a proof. The goal of science is to "effectively" answer a question for a "reasonable" person. These terms go more or less undefined as few people would agree on them and they're not really worth arguing over. The idea being, as a model is demonstrated to be effective/accurate, tweaked and then improved to be more effective, more and more people will be accepting of it. Once a model becomes so good in its explanatory power that most reasonable people accept it, the model is declared to be a "Theory".
For example, The Theory of Relativity, replaced the Newtonian Theory of Gravity. Was Newton wrong? No, Newton's theory was merely incomplete. There were observable phenomena that couldn't be explained, but what it did explain, it explained very well. Einstein didn't walk out on stage, set a copy of his theory on a table while saying, "Relativity Bitches!", then drop the microphone before walking off. After publishing his theories, scientists attacked and did everything they could to discredit the theory, only to show, over and over, that Einstein was correct. It took years before it was accepted by "reasonable" people.
It is important to note that in this context, reasonable people is not referring to your average 7-Eleven employee. The concepts that go into Relativity are often regarded as being too complex to be explained & fully understood by the average high school graduate. Reasonable people, in this case, refers to physicists. A 100+ years later, the only physicists that don't subscribe to Relativity, are crack-pots whining their fringe theories don't get equal time in the scientific community and the reason their theories don't get equal time is because their theories do not have equal or better explanatory power to Relativity.
Is Relativity complete? The answer is no. When you zoom in to the subatomic levels, Relativity breaks down and Quantum Mechanics (QM) takes over. QM is a tour de force of mathematics. In fact, no theory in science has a smaller margin of error when going from the mathematics to the statistical observations. The problem with the theory of Quantum Mechanics is that the rules it describes are even less intuitive than Relativity. People are fond of saying you cannot get something from nothing, but in QM, you can! Depending on how you define "nothing", after all, everything in Science has its caveats. The "rules" governing QM are so unintuitive, most college graduates cannot wrap their brains around it. Science is hard.
I'll say two things about Faith. The first, is that I find it surprising that anyone who is willing to accept anything on faith, by which I mean without empirical evidence, be it some form of deity or anything supernatural would require their science to provide evidence to the point of absolute certainty. It would seem to me that if you are a person who is open to ideas without evidence, then you would be even more accepting of ideas that do have evidence.Second, it is intellectually dishonest to use the word "Faith" in two different contexts and claim it to be the exact same word. Faith in a deity, a belief without evidence, is not the same as Faith in science or Faith in physicists when they tell me Relativity and QM serve us well in describing the universe. The latter use of the word faith is more akin to "trust". I have faith, i.e. I trust they can provide evidence of their claims regarding Relativity and QM, but to the degree I am mentally capable of understanding their evidence is on me. They've done their homework. They've demonstrated their expertise. It is up to me to become a "reasonable" person in their field before I can make any claims as to the verisimilitude of their work.