It does sound weird, and it was a thing I was cautious about when first reading about Pesso therapy. But the "synthetic memories" in no way replace your true memories just as someone who you ask to - in the therapeutic setting - take on the role of an "ideal parent" or "ideal partner" does not replace your real parent or partner. Instead, what you get is a real world experience of how the things could have played out differently, and this experience releases some tension that continued to influence your later interactions..

As an example - if a person was bullied in school, and has subsequently built up impenetrable walls in relationships, it could be helpful to re-enact an act of bullying in a safe setting. Only this time, the person is fully in control and can create an alternative ending - e.g. by letting an 'ideal friend' or an 'ideal parent' join in and stop the bullying. Now a synthetic memory is created - sure, it does not replace the old memory. But now you've got to experience that there are different outcomes possible, now you feel more protected.

The power of this method lies exactly in the experiencing. Before being exposed to this approach I thought my problems would go away, if only I could really really understand them. Now I see that experiences can be quite a bit more powerful than words and concepts. I can also see where all the rituals in human cultures are coming from.