Bishop James Pike on Heresy
[The word “heresy”] comes from a greek noun form (hairesis) of a verb in the middle voice (haireisthai) meaning “to take for oneself” — to choose. This concept corresponds aptly to the conviction that there can be no faith without personal decision…
There are… two principle ways people arrive at convictions. If a person’s beliefs, however many or few, are to be really his, he should choose maturely which of the two ways appears the more sound and then apply its methodology to select or form such beliefs. This is his heresy: his choosing for himself. The results of such choosing may also be heresy in the other, more commonplace, sense of the word… Therefore, if both the positive and negative meanings of hairesis are taken into account, every truely believing individual is heretical in the positive sense, whether or not what he has chosen to believe is heretical in the negative sense.
– Bishop James Pike, If This Be Heresy.