Interview with Dr Richard Schwartz for the British Psychological Society

https://thepsychologist.bps.org.uk/these-parts-will-fight-end-protect-you/

“Through my decades of work as a researcher and therapist I found the natural state of the mind is to have what I call ‘parts’ – to be multiple, to have these internal sub-personalities. These ‘parts’ are natural, not the product of trauma, and when they start out all of them have valuable qualities and resources that help us in our lives. So we’re born with them, either manifest or dormant, and they pop out at different times in our lives and start to help. But at some point trauma and attachment injuries force them out of their naturally valuable states into roles that can be destructive, that might have been needed when you were young to protect you but that later became anachronistic and outdated. “ see the link for the full interview