Experience and theory talk to each other.  New experience (hopefully) causes theory to be either re-worked or thrown out and replaced by new theory, which prompts experiments which in turn lead to new experiences.  

However, language is not very good at communicating experience.  There are may places where language can fail us.  I have the sense that my body-mind-experience has real limits, but where they are is often unknown. Those limits are sometimes presumed based on what I can remember, or think I can remember, of my own experience, they may even be based on what I've heard about my potential.  So I have limits but I don't know what they are.

Language can be burdensome.  

So there is experience (mixed with uncertainty), and there is a portion of that experience which can be felt as a kind of knowing.  And that knowing can be translated into language as some sort of metaphor, often metaphors on top of metaphors.  Some of those metaphors are unconscious.  Some are just useful because they point to some pivotal aspect of experience, but may otherwise be misleading. And these metaphors are put together into theories we then use to formulate experiments to test and replicate our experiences, and to share with others.  

If we could simply and effectively demonstrate and describe the experiments for replicating an experience we could, theoretically, by pass the need for theory.  But experience is uncertain, metaphors are imperfect, and experiments have artificial boundaries, so nature has stuck us with a never ending conversation between theory and practice.

So always approach theory with doubt.  There probably is another way to solve the problem, whatever it happens to be, no matter how insistant your teacher is about a particular method or your lineage is about a particular way of stating things.

Which seems like a good enough intro to this video which attempts to answer the question, why do we have a brain?  There is a funny joke about 2 minutes in.