For me, it seems that human maturity and spiritual maturity are intimately intertwined – and in a way just two views on the same process.
Human maturity, in an ordinary conventional sense, includes becoming more fully human. To see in oneself what we see in others. To deepen our sense of empathy with ourselves and others. To recognize our uniqueness as well as our common and shared humanity. To allow defenses to erode and a natural sincerity to emerge. To live a life for oneself as well as for the larger whole, in recognition of the intimate interconnections of all life.
Spiritual maturity also includes becoming more fully human. First, we find ourselves as the Witness, as the formless, unborn, that which is definitely not human and not even “alive” in any conventional or biological sense (although certainly alive in a different sense). Then, we integrate this into our human life. We explore our whole holarchy of being, as human self, as Witness and the rest of the manifest world. And this process looks very much like the process of just becoming more human in a conventional sense.
In a certain sense, we can say that both forms of maturation goes hand in hand. The first, conventional sense, is the ascending route. The second, spiritual form, is the descending route. And they are naturally part of each other.
Of course, the conventional form of maturity can proceed without ever being seen as explicitly “spiritual”, and it can deepen the transdual view even without conscious or explicit recognition of the Witness. Similarly, a spiritual path can take the form of less integration and even denial of our human existence. But to really go far and deep in the maturation process, it seems that both has to be present.
After writing this, I realize that the maturity I am refering to here obviously has two aspects: One is the health and integration at each level of development. And the other is developing within the various areas of spirituality, self, cognitive, emotional, interpersonal, moral, etc. Looking at it in this way it becomes more complex, although the general process is still the same.