A friend wrote to me today with this question.
Since we are not an I/self what is it that reaches nibbana. Who or what is not reborn? I know it is getting out of samsara but could you explain … I hope this question makes sense
Dear R.
This is a good question. Really it is what the Abhidhamma elucidates in such detail.
I reply in brief and hope it will encourage you to delve more into its depths.
As you know there is no self. Sabbe dhamma anatta - all phenomena are not self.
The Visuddhimagga XIX19
“There is no doer of a deed, or one who reaps the result. Phenomena alone flow on, no other view than this right.
XVIII24
“This is mere mentality-materiality, there is no being, no personXVII31
“The mental and material (nama rupa) are really here
But here is no human being to be found, for it is void and merely fashioned like a doll.
and
Sela sutta:
https://www.accesstoinsight.org/tipitaka/sn/sn05/sn05.009.bodh.html
This puppet is not made by itself,
Nor is this misery made by another.
It has come to be dependent on a cause,
When the cause dissolves then it will cease.As when a seed is sown in a field
It grows depending on a pair of factors:
It requires both the soil’s nutrients
And a steady supply of moisture.Just so the aggregates and elements,
And these six bases of sensory contact,
Have come to be dependent on a cause;
When the cause dissolves they will cease
So the teachings are uncomprising, there are only conditioned elements arising and ceasing.
This, of course, is not easy to grasp.
Dispeller of Delusion p.60
243.The characteristic
of no-self does not appear owing to not keeping in mind, not
penetrating the resolution into the various elements (nänädhätuvinibbhoga) owing to its being concealed by compactness. […]. **When resolving of the **
compact (ghanavinibbhoga) is effected by resolution into the various elements, the characteristic of no-self appears in accordance with
its true essential nature.
Now back to your question. As well as anatta, there are also dukkha and anicca (impermanence) that apply to all conditioned phenomena. sabbe sankhara anicca and sabbe sankhara dukkha.
As regards dukkha(often translated poorly as suffering); In fact every moment - even the most happy and pleasant are classified as dukkha - simply because they are conditioned to arise and pass away. And one way to consider the teachings is that the Buddha taught about dukkha, and he taught the path to end dukkha.
In brief Nibbana is the end of dukkha. There is no more conditioned phenomena. Nibbana does not arise or cease.
see also this;
If all conditioned phenomena are dukkha, how can an arahant no longer have dukkha mentally? - General Theravada topics - Classical Theravāda (classicaltheravada.org)
and