there is no self; yet there seems to be a never changing deeply seated, unfindable awareness attached to a human body
that observes the sensations that arise and pass away.
Yes.
This awareness continues to observe the body
Yes.
life after life.
Evidence for this?
It sits quietly as the body reacts and reacts until it discovers meditation and begins to stop the cycle.
Stops the cycle of ignorantly regarding life as 'self'? Yes, it can, as described in SN 22.99.
What is the nature of this awareness?
It knows, it cognises (MN 43); it arises dependent upon sense organs, sense objects (MN 38) & the mind-&-body (SN 22.82) ; that is all that can be said about it.
I can't make sense of the apparent contradiction that there is no self
A mirror does not have a 'self' yet a mirror reflects. Awareness/consciousness is similar.
For example, 1st the mind sees an object and, afterwards, the mind thinks: "I like that object". The seeing or awareness of the object occurs prior to the idea of "I". Awareness operates without a 'self'. The idea or thought construct of 'self' arises after awareness. There can be awareness without 'self' thoughts.
yet this 'awareness' has to follow a series of rebirths until this 'individual' is purified, at which time they are fully liberated.
No. The Pali suttas do not refer to a 're-birth' of awareness or consciousness. Instead, the Pali suttas refer to the 're-birth' of the ignorant 'self' concept. To quote:
There is the case where an uninstructed, run-of-the-mill person — assumes form to be a 'self'. That assumption is a fabrication. Now
what is the cause, what is the origination, what is the birth, what is
the coming-into-existence of that fabrication? To an uninstructed,
run-of-the-mill person, touched by that which is felt born of contact
with ignorance, craving arises. That fabrication (of 'self') is born of that.
SN 22.81
The craving that makes for re-becoming — accompanied by passion & delight, relishing now here & now there — i.e., craving for sensual
pleasure, craving to be, craving not-to-be: This, friend
Visakha, is the origination of self-identification described by the
Blessed One. MN 44
I understand that there is no self. There is nothing definable about the self which makes perfect sense to me.
OK.
But there is most definitely an awareness.
Yes.
What is this awareness?
Knowing, cognition; like a mirror reflects.
Is every living creature in the universe a unique awareness with identical properties?
Whenever there is some communication, there must be some awareness (however that awareness may not be fully reflective, like human awareness can know emotions but not act upon those emotions). For example, some plants know when an insect lands on them and they close up to eat the insect. These plants must have some awareness, however primitive.
Are we all the same awareness?
No. Now, my awareness is looking at a certain pink flowered tree outside my window. Since your awareness is not, the two awarenesses are obviously not the same awareness.
If so then why are we dealing with karma as discrete individuals?
Kamma is unrelated to awareness. In Pali, awareness is called 'vinnana', which refers to 'knowing' or 'sensing'. Where as kamma is related to intention (cetana) or thinking ('sankhara khandha').
The mental impacts of kamma (actions) are stored in the citta (mind-heart). For example, if a man gets angry at his wife and then feels regret the next day, the feeling of regret is related to the faculty of mind called 'citta' ('mind-heart') rather than 'awareness/consciousness'. Awareness only knows; only reflects.
Why human life has a 'citta' or an 'intelligent conscience', again we cannot say. It is probably just a survival mechanism.