Why Are There Four Gospel Accounts?

I recently ran across an interesting conjecture about this question while researching my next book. However, while it was compelling, I thought it best to test this conjecture against what Calvin penned about the four gospels in his Commentaries.

The first thing to notice is that Calvin values the Gospel of John differently from the synoptic gospels of Matthew, Mark, and Luke.

Concerning John’s Gospel in relation to the other three, Calvin says:

Yet there is also this difference between them,...