Greetings (again) Peter,
i&i have just realised that I did not reply to your specific request for criterion to separate the seeker from the non-seeker. I would suggest only one, and that is intent. A seeker, almost by definition, is one who self-consciously sets out to improve their understanding and awareness. A non-seeker is either unaware that such an improvement is possible, or regards their current state of awareness as being sufficient.
Love and peace
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