Let me preface the following by saying I'm not knocking anybody's good intentions ...
... working toward more knowledge of our inner and outer world is what many of my atheist friends do.
OK, but 'inner work' evokes a psychic or psychodynamic dimension, certainly not spiritual in the classical sense. I doubt if any would accept that God or the soul is the substrate of the inner world or that the inner world subsists by virtue of the soul and God.
If I was being at my most spikey, I'd say 'spirituality' has been repacked in the context of consumer culture. Its definition is so nebulous the term can mean and be applied to anything, determined not according to its own inherent meaning, but as a reference to the subjective sentiments of the user.
Repackaging because while one doesn't want all the burdensome stuff that goes with it, which is shuffled off and filed under 'religion', but nevertheless one does want access to the benefits, hived off and filed under 'spirituality'.
Classically, and I here to would point to the Orthodox (rather than the rather more accommodating Latin Catholic) world, in which there is and never was a distinction between religion' and 'spirituality', you can't separate the two: its'a all one,
theoria and
praxis are inseparable.
The 'repurposing' allows people to shop around and adapt a practice oriented towards a subjective and free-ranging set of choices drawn from disparate sources, conforming to a presupposition of self-being, -satisfaction, -comfort and -worth, etc.
... which is now chock full of aging hippies...
LOL, by far and away this movement gathered momentum under that influence – 'tune in, turn on, drop out' – the most irresponsible, nihilistic, up-its-own-arse philosophy of the last millennia! My father-in-law was a pagan practitioner and main player in the Albion Fairs which toured East Anglia and was the stomping ground of ageing hippies, New Agers, etc., etc. His was all about veneration of the Earth Goddess which was a projection of his own fantasies.
many are atheists or spiritual but not religious...who are into yoga, meditation, earth skills...again on a journey/quest of exploration and being in concert with Gaia and fellow travelers...
Quite, yoga and meditation are two examples that typify consumer appropriation of a religious
praxis.
Other forms of physical exercise are no better nor worse than yoga and there's nothing special about yoga once it's divorced as a
praxis from its parent
theoria. Likewise, the benefits of meditation can be replicated by listening to soothing music, reading poetry, or any practice where the individual disengages from the daily flow of 'demand' that is the engine of consumerism.
(And there are now questions being raised about the meditation industry's ignoring the cases of unfortunate psychological side-effects. Turns out meditation has its non-beneficial aspects that have been ignored until now.)
Again, Gaia is a case in point. The term was coined by Professor James Lovelock (a hero of mine) to suggest nature possesses a capacity of self-regulation to maintain and perpetuate conditions suited to its continuance. Nothing mystical or magical.
Then hippes/New Age/et al then jumped on this idea and the next thing we have Gaia the Goddess in a pseudo-religious context. All of which, Lovelock would insist, is utter nonsense.
Scientists in other 'popular' fields eg: cosmology, quantum physics, neuroscience, have decried the populist tendency to grab and misunderstand science and garb it in some kind of pseudo-spiritual hokum ... QP and the soul, QP and Platonism, that sort of thing. Even mathematics has its own versions — 'vortex theory', anyone?
Just goes to show ... religion: can't live with it, can't live without it.