Comment by hyperthesis

No matter how closely you look, there is always more to it. However you think things are, good or bad, you are "wrong". But you may have sufficient precision to make some specific technique operate. (The technique is predicated on an implicit theory simplifying how things are. Both the technique and theory are "wrong".)

In finding correlations between two things, a tricky bit is finding which two things (a thing can be an arbitrary composites of other things). When we do find a correlation, that becomes how we see it, and we think in terms of this particular simplifying theory of reality.

i.e. there are two issues: (1) reality is complex. (2) we simplify it.