Richard Carrier provides a review of the anthology Is This Not The Carpenter?. This book is a collection of essays by various scholars who, contrary to outbursts by anti-mythicists, argue that the non-existence of Jesus is a valid hypothesis to analyze. Some in the anthology argue in favor of his existence, some argue the contrary, but they all argue in a manner that assume the non-existence of Jesus isn’t a fringe theory equivalent with Creationism or Holocaust Denial.
Anyway, one scholar, K.L. Noll, seems to sum up my opinion about the historicity of Jesus:
[Knoll] argues that the quest for the historical Jesus is a waste of time, because “even if a historical Jesus existed and made an effort to found a movement of some kind” this “is irrelevant to an understanding of the earliest social movements that evolved into the religion now called Christianity” [p. 233] and therefore we shouldn’t have to declare any definite opinion on the subject of the historicity of Jesus–Noll assumes historicity simply because it’s as convenient an option as anything else
This is a good point. How does a historical Jesus help us understand how the subsequent movement of Christianity formed? Jesus had no role in the arguments about how his salvation worked or on the establishment and hierarchy of churches (those would have obviously been anachronistic), the debates about docetism/gnosticism, the Gospels contain very little — if any — teachings of his (meaning that the vast majority of teachings that Christians follow are the invention of later Christians thus a historical Jesus affords no explanation for them), he didn’t institue Apostolic Succession, didn’t argue for the current layout of the New Testament, and a myriad of other things.
All of those factors (and possibly more) shaped how Christianity eventually formed. None of those things can be explained by positing a historical Jesus, and are equally explained by a mythical Jesus. Paul, the Gospel authors, and other epistle writers in the NT cared very little if at all about a historical Jesus, so their writings are not explained by a historical Jesus. A historical Jesus is more like a MacGuffin: A plot device like the suitcase in Pulp Fiction. It is the initial drive of the plot, but after its introduction has no use in the subsequent narrative. For all intents, the suitcase might not have even existed but the story would unfold in the same way.
And if all that we can say about the historical Jesus is that his name was Jesus and he was crucified, there are way too many people in history who fit that mold; it would be like saying the historical George Washington was just a guy named George who was in the Army in the late 18th century. It doesn’t actually answer anything.
So this is why I’m agnostic about the existence of the historical Jesus. A historical Jesus might have actually existed (i.e. ontological probability) but our vantage point in history probably doesn’t allow us to claim that with any reasonable certainty (i.e. epistemic probability).