The story about Whitehead is that he lost his son Eric very late in WWI, and wanted to know whether he survived death. So part of his philosophical theory after the war was to see if he could make a view that was compatible with physics, but still allowed some kind of postmortem survival. In fact, the theory he ended up with only allowed the most meagre influence of mind (or God!) on nature. Since all 'actual entities' are physical, they are not really enough for survival at all. And when he talks about potentiality (which, if like 'power' might give us an idea about minds) he means 'merely potential', which is essential equivalent to 'merely possible'. Even in his physics, he does not have any idea about active powers or potentials. Yet, the mere fact that Whitehead had a theory that integrated mind and nature (however inadequate it may be) is enough to make people like Henry Stapp and Ken Wilber look back to him when they try to begin to make theories that connect mind and nature, and would otherwise be stuck completely.