@Joseph Maynor that depends on how you define it.. Enlightenment, as it is understood in all major traditions of enlightenment is binary.. It just means the complete destruction of separation and disappearance of the sense of a separate and personal self. In this sense, either you are enlightened or you are not.  But there is indeed a complete integration and embodiment of it (which takes time) and also an endless deepening.. But this is no longer a personal journey. There is no longer a psychological longing or a feeling of psychological lack after enlightenment. Enlightenment is the end of this lack and incompleteness but also the beginning of an endless abyss.