There are some problems with that. The Gospels were written with an agenda intended to lead and convince the reader to believe their side of the story. It is not an objective historical account.
The '500' are allegations made by Paul without any reference of corroboration. No other author (all of whom write after Paul) mentions it. But you will say it's an argument from silence. A significant event is worth repeating, especially considering that non of the Gospel writers even mention Paul. And, usually, credibility is assigned to multiple eyewitnesses, so it is very likely that such a number would have been mentioned again.
But eyewitness accounts are not reliable. The 1917 Fatima "miracle" of the "falling sun," and even "increased heat," in Portugal was "witnessed" by 70,000 people. It never happened. The sun was not falling. The people were simply hallucinating.
The apostles probably had visions of Christ after his crucifixion. My ex sister-in-law swore up and down that she "saw" my late brother standing on the balcony of their home looking at her two days after he died. Visions (especially in a state of trance) are mentioned in the Bible and are treated as "real" phenomena.
Because of that they probably came to believe that Jesus did resurrect. And when two or more confessed to similar 'visions' they became convinced that they all saw real resurrected Jesus.
But to believe they presented EVIDENCE of personal eyewitnesses. Paul in 1 Cor was basically telling them that if you don't believe me, there are hundreds of other witnesses. Furthermore the strength of Paul's statment (remember written no more than 30 years after the event) that IF Jesus had not risen - then EVERYTHING was in vain. 30 years is TOO short a period to develope a 'legend', that is less than one generation.
While the gospels may have a evangelistic component - you'll have to do better than that as far as DISPROVING the facts on that account. Otherwise you accuse the writers and the rest of the Apostles of lying - hardly the moral standard Jesus taught them.
The '500' are allegations made by Paul without any reference of corroboration. No other author (all of whom write after Paul) mentions it. But you will say it's an argument from silence.
Arguement within context - no other passage is a full out presentation of the resurrection. Where else is this level of presentation needed within the NT? Paul also speaks as he knows most of them.
The 1917 Fatima "miracle"
Is ONE event with an entirely different context from the resurrection encounters. Paul list the appearances to the disciples, himself, James the brother of Jesus, the gospels record the appearances to the women, the believers on the road to Emmaus, and finally Jesus' appearance to Paul. Each was situated in a different context and location.
Here is an expert opinion on group hallucinations
"The same hallucination may be experienced by two or more persons. If the event is entirely subjective, as all hallucinations are, how do two or 200 people manage to coordinate and synchronize their subjective lives? Recall our discussion of the role of expectation and misperception in the preceding chapter. It is expectation that plays the coordinating role in collective hallucination. Although the subject matter of individual hallucinations has virtually no limits, the topics of collective hallucinations are limited to certain categories. These categories are determined, first, by the kinds of ideas that a group of people may get excited about as a group, for emotional excitement is a prerequisite of collective hallucinations. The most common causes of emotional excitement in groups are religious, and, indeed, phenomena related to religion are most often the subject of collective hallucinations. Second, the categories are limited by the fact that all participants in the hallucination must be informed beforehand, at least concerning the broad outlines of the phenomenon that will constitute the collective hallucination. This may take the form of a publicly announced prophecy, for example, or someone suddenly looking up and saying, "Lo, in the sky!" or words to that effect. Things in the sky, or at least overhead, are the most commonly seen collective hallucinations: radiant crosses, saints, religious symbols, flying objects, sometimes all these in combination. Once the general type of hallucination is established, it is easy to harmonize individual differences in the accounts. This may take place during the hallucination or in subsequent conversations. "(Zusne & Jones 1982; "Anomalistic Psychology: A Study of Extraordinary Phenomena of Behavior and Experience", 135, emphasis added])
Catagorically, from the above three things are needed to produce 'mass' hallucinations.
1) expectation,
2) emotional excitement, and
3) being informed beforehand are factors that must be present for a collective hallucination to take place.
Gospel narratives show clearly that the Disciples and followers were NOT expecting a resurrected Jesus (John 20:9; Matt 16:21; Mark 9:9; Mark 9:31; Luke 18:33)
Their excitement (if you could call it that) was directed away from a resurrection, not in looking forward to it.
The factors were not laid out before hand, as seen in #1 above,they NEITHER understood NOR expected the resurrection, and couldn't initially process what had occured.
Visions (especially in a state of trance) are mentioned in the Bible and are treated as "real" phenomena.
A 'vision' has not tactile component. In the account by the women, the travelers to Emmaus, and the appearance to the Disciples - tactile evidence is present - the women were able to 'hold' onto Jesus, the travelers to Emmaus spoke for hours and saw Jesus pick up real bread and break it, to the disciples he had them touch Him, and ate.
Because of that they probably came to believe that Jesus did resurrect. And when two or more confessed to similar 'visions' they became convinced that they all saw real resurrected Jesus.
Does not track with the gospels, who record other incidents such as Jesus cooking by the lake - those were real fish the diciples ate at that time, or later history kosta. James the brother of Jesus would not have accepted that as he was opposed to Jesus.
Same with Paul, who was actively seeking Christians to persecute. If there was no resurrection, the Jewish leadership could have produced the body - and ended ALL questions then. They didn't and is tacit approval of the tomb being empty, and as Jewish sources, they would be very unlikely to even concieve of a resurrection as the cause - so the early polemics make up an excuse for the empty tomb.
You've perhaps spent too much time in a faith that extols mysticism over a rational God.
While Christianity is a supernatural faith, it is not a mystical faith. We have good and sound reasons for our belief in Christ, some of which is the evidence of first-hand reports, historical data and empirical results.
That, coupled with the good fruits of the Holy Spirit, witnessed, experienced and understood to be valid when submitted to the scrutiny of the Scriptures, all contribute to making the Christian faith more than "fables and the commandments of men that turn from the truth."
The "good news" is real.
"Rejoice, because your names are written in heaven." -- Luke 10:20