I ceased listening to Greer during one of his ‘special’ events where he claimed he would interact with actual aliens. When he failed to connect, he stated the aliens could sense some doubters in the crowd, so they would not present themselves.
I am not a fan of Greer but he is correct that “belief” is a critical component of “calling in” aliens.
There is a lot of literature on this topic.
The scientific materialist paradigm has major issues—and it just gets in the way of studying this topic.
Part of what is so frustrating about Greer is his huge ego and irritating personality obscures many solid insights on the topic.