A powerful spiritual practice like challenging your own limits and fears to the maximum, or meditation and fasting, or immersing yourself in a completely different environment from what you are familiar with until you know it truly. Or if these things sound too abstract, to take a strong dose of psychedelics alone or with others.
I'm pasting my response from above:
A powerful spiritual practice like challenging your own limits and fears to the maximum, or meditation and fasting, or immersing yourself in a completely different environment from what you are familiar with until you know it truly. Or if these things sound too abstract, to take a strong dose of psychedelics alone or with others.