i don’t understand why people need to believe in rebirth and karma to be a Buddhist, the quickest enlightenment is possible without believing in rebirth and karma and just by understanding this brief 1 paragraph bahiya ended his unsatisfactoriness completely
ud1.10
“Then, Bāhiya, you should train yourself thus: In reference to the seen, there will be only the seen. In reference to the heard, only the heard. In reference to the sensed, only the sensed. In reference to the cognized, only the cognized. That is how you should train yourself. When for you there will be only the seen in reference to the seen, only the heard in reference to the heard, only the sensed in reference to the sensed, only the cognized in reference to the cognized, then, Bāhiya, there is no you in connection with that. When there is no you in connection with that, there is no you there. When there is no you there, you are neither here nor yonder nor between the two. This, just this, is the end of unsatisfactoriness.”
I earlier thought this means not self but I was wrong we need to look at the expanded version of that brief 1 paragraph to understand it completely
the expanded version is here in malunkyaputta sutta
sn35.95
“Then, Māluṅkyaputta, with regard to phenomena to be seen, heard, sensed, or cognized: In reference to the seen, there will be only the seen. In reference to the heard, only the heard. In reference to the sensed, only the sensed. In reference to the cognized, only the cognized. That is how you should train yourself. When for you there will be only the seen in reference to the seen, only the heard in reference to the heard, only the sensed in reference to the sensed, only the cognized in reference to the cognized, then, Māluṅkyaputta, there is no you in connection with that. When there is no you in connection with that, there is no you there. When there is no you there, you are neither here nor yonder nor between the two. This, just this, is the end of unsatisfactoriness.”
“I understand in detail, lord, the meaning of what the Blessed One has said in brief:
Seeing a form
—mindfulness lapsed—
attending to the theme of ‘endearing,’
impassioned in mind,
one feels and remains fastened on it.
One’s feelings,
born of the form,
grow numerous,
Greed & annoyance injure one’s mind.
Thus amassing unsatisfactoriness,
one is said to be far from unbinding.
Hearing a sound…
Smelling an aroma…
Tasting a flavor…
Touching a tactile sensation…
Knowing an idea
—mindfulness lapsed—
attending to the theme of ‘endearing,’
impassioned in mind,
one feels and remains fastened on it.
One’s feelings,
born of the idea,
grow numerous,
Greed & annoyance injure one’s mind.
Thus amassing unsatisfactoriness,
one is said to be far from unbinding.
Not impassioned with forms
—seeing a form with mindfulness firm—
dispassioned in mind,
one knows and doesn’t remain fastened on it.
While one is seeing a form
—and even experiencing feeling—
it falls away and doesn’t accumulate.
Thus one fares mindfully.
Thus not amassing unsatisfactoriness,
one is said to be in the presence of unbinding.
Not impassioned with sounds…
Not impassioned with aromas…
Not impassioned with flavors…
Not impassioned with tactile sensations…
Not impassioned with ideas
—knowing an idea with mindfulness firm—
dispassioned in mind,
one knows and doesn’t remain fastened on it.
While one is knowing an idea
—and even experiencing feeling—
it falls away and doesn’t accumulate.
Thus one fares mindfully.
Thus not amassing unsatisfactoriness,
one is said to be in the presence of unbinding.
“It’s in this way, lord, that I understand in detail the meaning of what the Blessed One said in brief.”
“Good, Māluṅkyaputta. Very good. It’s good that you understand in detail this way the meaning of what I said in brief.”
so I think instead of not self in that earlier brief 1 paragraph Buddha said that cessation of non mindfulness, attending to the theme of ‘endearing,’ impassioned in mind, feeling and remaining fastened on senses objects, the proliferation of feelings and the duality of greed and annoyance are the keys to end all unsatisfactoriness, even malunkyaputta’s understanding of that brief 1 paragraph still don’t include the concept of rebirth and kamma
so rebirth and kamma definitely are not core Buddhist concepts, but I don’t disagree that they may be useful and helpful to end unsatisfactoriness
if you are satisfied now you wont have greed, the fact you still have greed means there’s still unsatisfactoriness there, annoyance is the same
in stoicism it’s the same you generally tend to avoid reactions over external senses objects which is the duality of like of dislike, the stoic founder said we shouldn’t react to things outside of our controls like external senses objects because it’s useless and unnecessary just accept the external phenomenon as it’s
based on that malunkyaputta sutta we know that arahant still experience unsatisfactoriness thus they are normal human being the difference is they have no greed and even annoyance to things they experience while normal people are shot by 2 arrows of experience and reaction, the arahants are shot just by 1 arrow of experience