What to believe?

Sometimes yoga lore conflicts so strikingly with what I have learned as an educated westerner that I do not know how to think about it. On one hand, I know what yoga has done for me, and this effect cannot be doubted, even though I am certain that a dozen experimental scientists who put electrodes on the sides of my skull as I practice could not perceive it. On the other, yogis like Mr. Iyengar speak about the effects of yoga in a way that makes me at the very least skeptical. This is perhaps why I have preferred to do yoga to reading about it.
Today, for example, I went to Denise's pranayama workshop, where a curious and rather attractive doctrine was imparted to me, the notion that people who get along well do so in large part because they breathe habitually out of the nostril on the same side. On one hand, being a dim westerner, I had never before noticed that we only breathe out of one nostril at a time, though which one this is changes periodically. On the other, to be told that personal likes and dislikes can be attributed to one's preferred nostril was a rather quaint idea for me, to say the least. But I guess it is another way of saying that we think alike, and if it is in fact true that the nostril one favors can be linked to the side of the brain one favors, and this side of the brain is linked to one's interests and values, I could construct a causal chain of a sort that would come down to the same sort of things as a western notion of why one prefers the company of particular other people. Does it matter after all how one describes something if we are in the end talking about the same thing?