Because modern spirituality has ruled-out in advance any role for God, then meaning can only be in memory - which will surely erode, become distorted and end with death; or in the obliteration of memory by 'living in the present moment' without self-awareness - which is to destroy what it is to be human.
Thus modern spirituality is peculiarly split in its attitude to memory.
To be 'spiritual but not religious' is a very mainstream sort of thing nowadays - as evidenced by the large 'Mind, Body and Spirit' section of bookshops, and the multitude of New Age activities and artifacts.
This can briefly be characterized as 'anything but Christianity' - being broadly positive towards all religious traditions past and present except actually-existing Christianity (which is regarded as one or another type of 'fundamentalism')
(Note: This was me, up to about 2007.)
Among those who are spiritual but not religious, there are people who seek and collect epiphanies, spiritual experiences, moments of insight and enlightenment - relying on their brain-located memory to store, preserve and retrieve them intact and as required (in order that life have meaning).
Yet all this store will inevitably melt-away and become muddled with time.
And since they believe that there is nowhere for memories to be except in the brain, when the brain goes so do the memories (which are probably feeble and biased anyway), and then they are utterly annihilated, as if they had never been.
So, to live utterly dependent on one's own personal memory is at most a temporary stop-gap; and ultimately, it is futile.
And there are people who seek to escape from dependence on memory, and live in the present moment - believing that the present moment is real, but memories an illusion, and concerns over the future are a snare.
They seek to lose all attachment to the world, to cease to be self-aware: indeed to dissolve the illusion (as it is regarded) of being a 'self' distinct from reality. They seek just to BE.
In the West this has been a strong strand of spirituality, from the Romantic Movement of the late 18th century (and in the USA, the New England Transcendentalists a little later).
And since the Beat Generation of the 1950s and Hippies of the 60s, the main reference has been to 'world religions' - whether Eastern and meditative, or aboriginal and shamanic.
There are various disciplined paths to the obliteration of the self - an arduous and prolonged training in something like Zen; or else there is an instant and reliable obliteration of the self and memory by means of intoxication with drugs, or the triggering of any other cause of acute delirium.
Or, for a more lasting - indeed permanent - solution there is death: suicide - that does it too.
Combining the two paths of intoxication and suicide is also quite popular since it was pioneered by Beats and Hippies - i.e. to drink or drug oneself to death, and call the process a 'spiritual' path.
So there are these two opposing strands in modern New Age spirituality - the one depends on a perfect and long-lasting memory, the other on destroying both memory and planning as evidence of a false self and attachment to the world.
The first is refuted by everything we know (from our own experience, as well as science and medicine) about the contingency and evanescence of memory; the second is a covert death wish - specifically a wish for 'the self' to die - coming from a cultural context of religions where 'the self' is expected to survive death, and either be reincarnated in a nightmare cycle of eternal suffering, or consigned to a state of eternal misery (such as Hades, Sheol, or Hell).
From my own experience of banging my head against the possibilities, neither of these make sense as a way of living - so modern New Age spirituality is, in practice, not taken with ultimate seriousness; in practice, it is a tactical (not strategic), self-administered psychotherapeutic lifestyle option: just a collection of spiritual band-aids and stop-gaps.
The only way-out from this is to re-examine the primary premise of 'anything but Christianity' - at least, minimally, to the extent of allowing for the reality of a personal God.