The “group hallucinations don’t happen” meme is a red herring. By focusing on whether it’s possible for multiple people to share the same hallucination, apologists take for granted that the disciples did in fact all see the exact same thing, which goes far behind the evidence.
“I accept that there was a collective appearance to the twelve, but details are lacking. Even if the canonical accounts of this experience are word-perfect memory (which I do not believe), why did some of the disciples, as all our sources relate, have doubts?...
And did they all see exactly the same thing? Did any feel pressure to go along with the others? And what became of these people? Acts has them, as a group, running the primitive community in Jerusalem; but it gives us stories only about Peter, James, and John...
We know nothing about the post-Easter history of the rest. If we rightly ignore later, unreliable legends, the silence about these people is absolute. Did some of them give up and go home after a few weeks or months? If they did, we would probably not know it...
Certainly nobody can show that they stuck it out for life. It is equally worrisome that, regarding the purported appearance to the five hundred, we cannot name a single individual. Or the place in which the event happened. Or what was seen. Or what was said, if anything at all...
We just know nothing about this stupendous event, other than someone’s bare claim that it happened. What sort of evidence is that for a critical historian?” - Dale Allison, Philosophia Cristi Vol. 10, No. 2, 2008, 325-26
"The accounts given by the different witnesses of a collective apparition often appear to tally with one another, and this has led some writers to comment with amazement on the precise coordination required to enable a number of people to see an identical figure...
..., as if viewed from the appropriate angle in each case. But as a matter of fact we do not know how precise the correspondence is between the images perceived by the various subjects...
“Things can be seen by many people independently of one another, or even simultaneously, which are not physically real. Also, the association-process of many people often have a parallelism in time and space, with the result that different people...
simultaneously and independently of one another, can produce the same new ideas, as has happened numerous times in history.” - Carl Jung, Flying Saucers: A Modern Myth (Princeton University Press, 1978), 13