The Outrageousness of Science?

After reading the first few chapters in our textbooks and the pieces about Fechner last week, I have been left wondering: what makes a quack? What makes someone's ideas about psychology, or any science for that matter, more ridiculous than the next? Or more valuable than the next? In the first couple chapters of our book (and I'm assuming through most of our readings on the history of psychology), we encounter many individuals who contributed greatly to the field. Yet during their time, many were often thought of as outrageous with unfounded beliefs. Those who were denied these claims by crying "uncle" in the form of: "It's science!" Even more scientists of the time had ideas that were greatly admired yet seem common sense to us now.

Here's an example of a scientific idea that was respected during its time (and afterwards). Maybe I am missing something, or maybe it's good that I am in the field of social science and not natural science, but Fechner's research on psychophysics is difficult to understand. HOW specifically did he measure sensation? HOW specifically did he measure stimulation? If, in fact, according to Wozniak, "mental processes are internal, private, subjective, and cannot be measured directly," how did Fechner come across a way to measure these things? Fechner measured his findings "in terms of the relative increase in physical energy required to bring [mental intensity] about." I'm struggling to see the way in which Fechner could substantiate this data. In fact, if he found a way to measure mental processes - the private, subjective, inner workings of our minds - I think a lot of psychological researchers would be out of a job!

Back to my first point, I've started to wonder... what psychological ideas, methods, processes, and theories do we have now that will look outrageous fifty years down the line?