This philosophical approach does not lend itself to rigorous empirical testing. Yalom wrote a text acknowledging this. I have previously urged you to consider testing. In this case, the founders do not state that their theory can be tested. Their assumptions and attitudes guide their interventions with clients.
Therapists have to be open to changing themselves, as they are involved with their clients.
They come to see that they are responsible for their own existence and problems and these are not caused by external causes. They examine their values, beliefs and assumptions to determine their validity. The middle phase. Clients examine their present value system. They find the kind of life that they want to live and what gives their life meaning.