Siebe:
What I explained is what is in SN 22.1:
“4. Sakkaya comes from “sath” + “kaya”, where “sath” means “good” and “kaya” means “aggregates”. So, sakkaya ditthi is the wrong perception that the five aggregates of rupa, vedana, sanna, sankhara, and vinnana are good and beneficial”.
Sakkaya ditthi is the attachment to the five aggregates based on the conviction that those rupa, vedana, etc are good for oneself. While that may be true in the short run, it is not true in the rebirth process where one could be born an animal or worse.
– This is why it is not possible to grasp Buddha Dhamma without taking a long-term view. If one does not believe in the rebirth process (and that one COULD be born an animal or worse), it is impossible to grasp Tilakkhana and get rid of Sakkaya Ditthi.
– When one loses Sakkaya Ditthi, one’s mind becomes free of a large fraction of defiled thoughts. That is the first stage of “cooling down”.
However, as I said elsewhere, different people comprehend things differently at one’s own level of understanding.