A law or limitation of being which is discovered as 'just how things are', that is from the outside, might be or at least seem inexorable, but can never be necessary. One would immediately begin thinking of ways to get around it. For a law to be necessary, like the Kantian categories, it must have been freely chosen, and thus be contingently necessary. The choice, however, might be an inevitable one, given a true knowledge of one's own nature, a result of certain prior choices, or decisions made before there was any possibility of knowing that you'd chosen, so in that sense the contingency prior to necessity would itself be a necessary one. All of this is playing with levels, is it therefore entirely without purpose, or is it an 'operator' of consciousness?