Let me provide the suttas that describe Sakkāya Diṭṭhi:
In the “Cūḷavedalla Sutta (MN 44)” Ven. Dhammadinna explains it to her former husband Visakha:
“..Kathaṃ panāyye, sakkāyadiṭṭhi hotī”ti? “Idhāvuso visākha, assutavā puthujjano, ariyānaṃ adassāvī ariyadhammassa akovido ariyadhamme avinīto, sappurisānaṃ adassāvī sappurisadhammassa akovido sappurisadhamme avinīto, rūpaṃ attato samanupassati, rūpavantaṃ vā attānaṃ, attani vā rūpaṃ, rūpasmiṃ vā attānaṃ. Vedanaṃ … pe … saññaṃ … saṅkhāre … viññāṇaṃ attato samanupassati, viññāṇavantaṃ vā attānaṃ, attani vā viññāṇaṃ, viññāṇasmiṃ vā attānaṃ. Evaṃ kho, āvuso visākha, sakkāyadiṭṭhi hotī”ti.
Translated: “..how does sakkāya diṭṭhi come about?” “It’s when an uneducated ordinary person has not been exposed to the teaching of the noble ones. They have a wrong vision about rūpa (material form) in 4 ways: regard rūpa as “mine”, or “I” as rūpa, or rūpa to be “in me”, or “I” to be “in rūpa.” [My comment: Those are the ones with uccheda diṭṭhi; see my post above on January 31, 2021, at 9:13 am. These are 4 ways]. Then there are others who regard each of the mental factors vedana (feeling) … sañña (perception) … saṅkhāra ( ways of thinking) … viññāṇa (consciousness) as “mine”, or “I” as those, or them to be “in me”, or “I’ to be “in them”. [My comment: Those are the ones with sassata diṭṭhi; see my post above on January 31, 2021, at 9:13 am]. Thus they have sakkaya diṭṭhi in 16 different possible ways]. That’s how sakkāya diṭṭhi (sometimes translated as identity view) comes about in 20 ways.”
Per my posts above, it is easy to this when one can see a lifestream switching from bhava to bhava.
– When in a human bhava, one has the form of a human. And one’s “mental entities” are those in the broad category of humans.
– When born an animal, the form would be that of that particular animal. That animal would not have the “higher level of consciousness” of a human.
– Born a Deva or Brahma those would be again different.
That is why those 20 views are wrong.
In each bhava, those entities arise according to causes and conditions that led to the arising of that bhava described by Paticca Samuppada: “avijja paccaya sankhara” leading to “bhava paccaya jati“.
– Apuñña abhisaṅkhāra would lead to births in the apayas.
– Puñña abhisaṅkhāra would lead to births in the human, Deva, and 16 rupāvacara Brahma realms.
– Āneñja abhisaṅkhāra lead to births in the arupāvacara Brahma realms.
See the recently re-written post: “Saṅkhāra – What It Really Means” for details on different types of saṅkhāra.
The above description of Sakkāya Diṭṭhi is discussed in many suttas: “79 results for attato AND Samanupassati“