The psychologist Barry Sullivan (I believe that's his name; I may have to go check) has written extensively on our tendency to fall in love with our own theories about how things work. Because we become so very attached to our mental constructions, we defend them passionately, even in the face of compelling evidence to the contrary. This is why everyone knows what really happened concerning the Kennedy assassination, what's really behind the UFO phenomena, why my superstitions are better than your superstitions, why your take on the dhamma is superior to my take on it, etc. We defend the balustrades of our mental sandcastles like knights fighting for their king's honor. Even Buddhists, warned not to attach to rites, rituals, attitudes, beliefs, etc. aren't immune.
Oddly, according to research, the more irrational the belief, and the more compelling the argument against the belief, the more passionately the tendency tol defend it. Add to this that we seem to be hard-wired to NEED an element of supernatural to survive (another interesting line of research I stumbled upon in Scientific American) and no wonder the Internet is clogged with bitter--and in my opinion, fruitless--arguments over issues that can never be resolved. Like Evolution vs. Creationism, about which I could personally give a rolling doughnut. Wave those Bible and rattle those fossilized bones somewhere else; any dogs I had in that fight died long ago and rebirthed as devas.
Ludwik Fleck, a physician writing in response to the Logical Empiricist movement of the 30s and 40's, described the idea of "thought-styles," which are formed by training and socialization. He believed, and justifiably, that under the influence of a specific thought-style, it became virtually impossible to think or even SEE any other way. Groups of people sharing the same thought-styles Fleck called "thought-collectives." A thought collective is defined as "a community of persons mutually exchanging ideas or maintaining intellectual interaction." An extreme example would be the Nazis. I'm not evoking Godwin's Law here; Fleck was a Polish citizen who was detained at both Auschwitz and Buchenwald, and somehow managed to survive, so he had ample opportunity to observe his theories. Fleck's point, which he wrote about extensively in scientific journals, was that even with trained observers, two different observers looking at the same phenomenon could arrive at totally different conclusions, based on the influences of their respective thought-styles, which would exert irresistible biases on both the focus of, and the interpretation of their observations.
Since Buddhists are a thought-collective, and Theravada are a sub-collective, our thought-styles are going to overlap in certain ways, but since we also come from different generations, cultures and social groups, those thought-styles come into play as well. So although we're all studying the same body of knowledge, our thought styles will create personal biases which affect how we perceive and interpret this knowledge. Unless we're very, very careful. I don't see endless debate getting anyone anywhere; it's an illusion of activity in my opinion, like the salesman who comes to work, sharpens his pencils, organizes his desk, makes a list of all the people he's gonna call, and then hey--it's lunchtime. And not a single call made.
This coffee is very, very good