Why can the 12th house indicate both suffering & internal spirituality? For many though not all, suffering leads to a larger focus on spirituality (or introspection, meditation, etc.).
Saturn, lord of boundaries, has its joy in the 12th, & containment inside boundaries can often equal suffering (prisons, hospitals, other 12th house significations), while being outside boundaries can mean spirituality/enlightenment.
In other contexts, such as the 7th house, staying within boundaries isn’t necessarily a negative thing, but in the 12th, they can feel limiting, unless we find a way to transcend them. This is not the spirituality of the 9th house, but one that’s been wrought as a coping device.
Rhetorius lends support to this idea by describing the 12th house as “between worlds,” a place where one strives to reconcile the suffering of the material world with the spiritual plane. It deals with pre-birth events, which can include where the soul resided prior to the body.
“Between worlds” also indicates why those with a prominent 12th house may feel like an era of life ended but a new one hasn’t yet begun. The 12th house rules liminal spaces – the space in between when you’re moving from one cycle to another.
This can be as literal as a stairwell or hallway, or as metaphorical as someone who has just gotten divorced but hasn’t yet found a new partner or place to live that feels like home.
No matter how proactive they are, those who have their Ascendant ruler in the 12th may go through long periods of life when they feel like they’re just… waiting.
While Vincent Van Gogh was confined in a mental institution, the view outside his barred window inspired him to paint “Starry Night”… though he neglected to paint the bars. This perfectly emulates how the 12th house can be a combination of suffering & transcendence.