The scope of knowledge we humans have collectively accumulated over the past few thousand years has reached a point where it surpasses the learning abilities of even the most dedicated genius. As such, we are forced to specialize our knowledge, to become experts in one or a few fields, and our investigations into other subjects can only go so deep, considering the limited span of human life. At the same time, however, we are pressured from all directions to accept certain things as true which don't fall into our own categories of deep knowledge. Biologists expect us to accept the conclusions of their study of evolution, despite the subtly vast range of information such studies deal with; physicists expect us to accept the conclusions of quantum physics, despite the years of learning, study and research that are required to grasp the main notions of quantum theory; pastors and apologists of religion expect us to be scholarly masters of every verse and phrase of their 'Holy Book of Choice', despite the fact that so many such tomes exist and are filled with so many extraordinary claims that require extraordinary evidence; and the list goes on.

So why is it I generally tend to accept the conclusions of scientists, but not other sources, such as pastors, when I lack the qualifications to thoroughly judge the conclusions of either type myself? The heart of the answer lies with the scientific method, a method for which I have the utmost respect. The scientific method is the opposite of dogmatic - it is self-correcting. It can be revised as new data comes in; in other words, it stretches the theories and laws around the facts, rather than attempting to stretch the facts around the theories and laws.

Also, the scientific method is an honest one: it doesn't make claims to perfection or absolute truth; scientific conclusions are accepted only for the time being, as the best explanation given the current facts. Those conclusions aren't touted as absolute truth no matter how long they go without being falsified, for the possibility is always left open that something could come along that shows the conclusion was wrong. Science corrects itself (although the scientists themselves may sometimes hold dogmatically to their favorite conclusions, but time seems to always favor the new corrected conclusions over the old dogma). Many other things, religion for example, generally do not offer such possibilities. It is claimed as absolute truth by Christians that Jesus is the son of God, died for humans' sins and resurrected, etc. If data were to come in to the contrary, religionists would not reconstruct their conclusions around it, but attempt to either twist the data to conform to their views, or else ignore it altogether. In this way, religion is (to it's adherents at least) often non-falsifiable.

Another reason I tend to listen to scientists is that the claims they make are at least theoretically falsifiable by me. If I decide to, I can go into biology, learn all the detailed inner workings of cells and organisms and life itself, and determine whether or not what I have been told by biologists is correct. Scientific experiments are generally only accepted if they are repeatable; in other words, if any person could perform the same experiment and get the same result. Thus, I could theoretically perform the experiments that led up to a given discovery, I could trace out the history of the theories and hypotheses dealing with it, and I could determine for myself whether they are sound or mistaken. While I can't actually do this myself for every field, there are countless people each day who go into all these various fields and majors and specialties, and I have faith (not in the religious sense of the word, but based on what I think are reasonable assumptions) that at least some of these people would discover any problems with currently accepted scientific concepts, and that if their results were properly repeatable, etc., their criticisms of modern theory would eventually be considered and accepted. The more egregious the error in current theory, the better the chance someone will discover the error, spread it to others in the same field who can properly falsify the information, and the theory will be revised. And so while I can't actually go into all the fields of science from which I accept many general conclusions, I have reason to believe that the conclusions I am given are in fact the best science can come up with using the given data.