If we wipe ourselves out, and there’s not a human brain left in the cosmos, what happens to God?

I have a better question that has higher probability to be answered. Where was God before human brain?

The study does not continue (that I saw) to show how researchers tested for the actual presence of God generating or influencing the nuns’ brain activity.

They were instructed to 1) not to intentionally think of anything 2) recall the emotions of a memory of their most intense union with another human being 3) recalling and reliving their most significant mystical experience (source)

In practice the nuns repeatedly entered unio mystica.

“Mario Beauregard […] and doctoral student Vincent Paquette’s Templeton-funded study of contemplative Carmelite nuns in Montreal, using fMRI and QEEG (quantitative EEG), with Hood’s Mysticism Scale as an evaluation tool. They wanted to study whether specific brain states are associated with mystical contemplation, in particular with mystical union (unio mystica), a state in which the contemplative Christian feels completely united to God. Such states typically result in greater compassion and healthier attitudes and behavior (also a common result of near-death experiences). […] The 15 Quebec nuns, aged 23 to 64 (mean age 50), had collectively spent about 210,000 hours in prayer.” (source)

They captured a ton of theta waves, indicative of deep meditative states. For a Templeton-funded study it was pretty objective.

That being said — what should scientist measure/test as a presence of God?

Are these common and experiencable personalities that effect unrelated people the same way a product of human brains? Of the plant itself? Of a real spirit associated with the plant?

What we know for sure is that it’s a chemical union of cannabinoid receptors (mainly in brain) and respective substances within the plant. So, I would say that it’s a brain-rendered nature of the plant itself. Call it spirit if you wish (spirit, as in essence). In the same way one can say that unio mystica is a mental union with personal concept of God.

Anyone who performs studies that support extra-body travel as a real thing are trashed as disreputable.

Maybe because the term itself (out-of-body experience) is BS. Essentially all those travels are in-mind. There’s a story: Two men were arguing about a flag flapping in the wind. “It’s the wind that is really moving,” stated the first one. “No, it is the flag that is moving,” contended the second. A Zen master, who happened to be walking by, overheard the debate and interrupted them. “Neither the flag nor the wind is moving,” he said, “It is mind that moves.”

There is however one thing that Buddhism is silent about (and quite rightly so, because it leaves to practitioner to discern it for themselves by seeing through the nature of perception — not the easiest path), and that is what is aware of that moving mind.

You may be satisfied that these things are tricks of the brain. I’m not.

I’ve never labeled them as such. To me they are functions of brain/mind.

I doubt Craig would agree with you about those heavens and hells being real.

I don’t know, but what I do know is that they are not elsewhere. Where I am right now, the same what is perceived as physical reality is also perceived as heaven, hell, or whatever. And it’s not even hidden in different dimensions. It’s the same existence. Just perceived in many different ways.