Once upon a time, cause and effect were simply part of math class. As absurd as it sounds, I didn't extrapolate the "if..., then..." lessons of math class out into the "real world". I didn't recognize in math a language that described the natural world (though I hope my teacher were at least trying to make that clear), and I didn't recognize that most of my actions sprang out of if-then related compunctions, be they desire for the promised or fear of the alternative.
My brain only went so far as to tell me what I should do, not why, leaving reason and logic fully out of the equation. It was never "if I study, I will learn more", but just "I should study." It was never "if I eat ten cookies, then I will feel sluggish", but just "I shouldn't eat ten cookies". In retrospect, it seems so obvious that the outcome scenario - the "then" statement - was missing from so much of my daily thought processing and decision making. And while the outcomes of my examples seem painfully clear now, at the time they didn't. I assumed my sluggishness was just sluggishness, not a sugar crash. Studying more didn't always mean I had learned more, but I didn't necessarily have a ton of say in what I was supposed to be learning, so I didn't notice.
Noticing comes from observing, which can lead into scientific exploration, just like the old process of yoga, of discovering, without assumptions, what will stimulate the human body and mind to a particular effect. This patient process of trial and error challenges most of us because living in uncertainty immobilizes. But somehow we need to move forward nonetheless, and operate on principles that appear to be effective while we keep looking for more definitive answers.
Sounds like science, right? There's a reason I remember learning about cause and effect in math class and now link it to the scientific method. To determine the cause of an effect or the predictable result of an action requires investigation - observation, hypothesis, experiments, and theories - to arrive finally at something that might be the truth. Yoga works in a similar manner, using what it takes to be true, and continuously exploring the rest (and then some, hopefully).
Universal truths must be determined using methods that eliminate individual bias as much as possible. Individual truths, i.e. the truth of one's own experience no matter how subjective, should be examined with equal care. We need a scientific method for ourselves!
Given that science has trouble keeping all subjective bias out of research, it seems like there would be little hope for any one unchecked individual to do so. And yet, the practical tools of yoga provide a means to begin to do just that: examine self within a greater context and give meaning to subjective experience without it contradicting "objective reality". Yoga is an old tradition with many forms and particularities. These will continue to grow even more diverse and plentiful. Its primary objective does not change, even if we quibble over defining the parameters of that objective.
The yoga lineage in which I study offers up the science of yoga, or yoga as a science, wherein the tools we employ in personal practice have been used with reportedly reliable consistency to cause particular effect. Hence, while the individual experience of them is where one's own study must be focused, the body of past stories combined with personal experience gives teachers some assurance that these can be passed on to students to create a similar effect. (We must always observe the actual effect and leave space for a unique experience that surprises us.)
Yoga is a collection of causes and their effects. When you use the practices that create the effects you need, whether you call them yoga or not, you're just being practical.
hari om tat sat!