Not that it is right or fair to contrast history with physics, but with a physics claim I could concievably reproduce the observations and check the math. Even if I won't actually put in the work, the path for checking any claim seems reasonably clear.

Really? If you aren't a physicist, what are the odds that you are going to be able to reproduce the experiment? Do you have a spare particle accelerator lying around? Better yet: do you have the specific particle accelerator that was necessary to get the data in the first place? (Because in many cases, experiments are pretty hardware-specific.)*

Do you have enough training to really check the math on anything but the most trivial work? Do you know how to ask the right questions and make the right assumptions? (Let me give you a real example: how on Earth would a non-physicist evaluate even the value, much less the truth status, of a paper like this? I picked this particular paper basically at random, but I think it illustrates the problem well. The best I can do with this, as someone who is not a physicist but has read plenty of popular physics works, is something like: "well, this person works at a university... but I don't really even know if that's a good university... I can understand some of the words... but I really don't really understand the stakes, the math, or the outcome." I could search around to see if or how it was cited by others, but that doesn't really resolve the underlying difficulty of expertise. The paper could be total nonsense or it could be something that might win a Nobel Prize in the future — how could I tell the difference? I really can't.)

Here's what you're really saying: other physicists can presumably check out physical claims. If you're really a layman, though, you probably can't — unless you change that and become a physicist.

This is how expertise works, and expert claims work. It is no different in history. The idea that laymen can wade in and "check the facts" is totally anti-expertise, and frankly often leads to a lot of silliness.

If you really care about expert knowledge you are, to some degree, at the mercy of your experts. That's unsatisfying, to be sure. But it is literally the definition of expertise. You're at the mercy of experts when you take your car in to be repaired as well. That does not mean you cannot become an expert — but it's not something you can quickly do. That does not mean that you cannot consult other experts (via, say, the Internet, or your library, or whatever), but your ability to weigh contradicting expert claims will be necessarily limited (in the same way it would be if you were trying to weigh contradicting expert claims about anything else; you are somewhat at the mercy of whichever expert is most rhetorically skilled).

We have systems in place to try and help people identify experts, and weigh claims. Reviews (and peer review in general) are part of that. Books, articles, etc. Specialized degrees that say "this person must not be a total crank, because a Prestigious University gave them a PhD."

But if you want to learn how to carefully evaluate historical claims you need to, to some degree, either trust experts or become an expert yourself. And the latter is difficult. And if you do it poorly, you can easily become a crank, a non-expert who thinks they are an expert.

(I had someone recently tell me that they thought this approach was "elitist." I just want to clarify: it is not. It has nothing to do with the elite, except as much as educational opportunities in some countries is limited to the elite. In that case, the country's educational system is elitist, but the notion of expertise is in principle not — anyone, with the right amount of time and effort, can become an expert. But the idea that everyone can be an expert if they just "check the facts" or look into it for themselves or even read other experts' views, all of that is false. It is more than that.)

* These questions are not merely idle ones. How replication occurs in fields that have singular, specialized facilities, like much of physics, creates a tricky epistemological situation, and has been implicated in several cases of claims being unable to be replicated — sometimes because of the difficulty of transferring the experiment from one experimental setup to another, sometimes because of error, sometimes even because of fraud. I only note this because you've taken physics as something of a gold epistemological standard — it has these issues as well, as historians and philosophers of physics have long studied.

Not that it is right or fair to contrast history with physics, but with a physics claim I could conceivably reproduce the observations and check the math.

You're saying that you could conceivably reproduce the observations of CERN by building a particle accelerator and then check the math of these observations that have been made by some of the most highly trained experts in the field of physics? That would be some pretty impressive ish, dude but also sounds a bit dismissive towards people who have spent years of their life becoming experts in the field of physics.

But now I sounded inappropriately dismissive and I apologize. I will now try to explain how historians come to their conclusions regarding the veracity of certain claims and will try to give several tips on how someone without historical training can become better at discerning bullshit claims from not bullshit claims.

Like any other academic discipline, history also subscribes to the idea that within every academic work, the reader must be given all the necessary information should they chose to want to falsify a claim or interpretation. Hence, academic books in history will feature footnotes where an information is from, an introduction laying out the state of historiography up that point, the question pursued and the theoretical and methodological framework used in an attempt to answer the question posed. This is in effect the same as with a study in physics telling you the experimental design, the observations that resulted from that design, the math used for it and the interpretation of what these observations mean within the larger context of what we know about the world.

Now, it is obvious that not every reader might have all the tools to immediately go out and start falsifying/verifying the results of a historic study immediately. As you said, they might not speak the language, might not have the time and finances to visit the archives and so forth. This, again, is similar to other academic disciplines. Not everyone is trained enough in math or has access to the necessary equipment to reproduce the observations of an experiment in physics, to say nothing of the background knowledge to interpret them. This is why the academic community has devised methods of quality control: In order to publish an article or an academic monograph they have to undergo peer review, meaning people from the same field of study with a comparable level of expertise in whatever sub-field is dealt with, read the article – often without knowing who its author was in order to increase the willingness to critique properly – to check what was written, make critical comments and annotations and eventually recommend an article for publication or not. While not 100% perfect, this is the same in virtually every academic discipline, from history to physics and works to weed out people lying, claiming bullshit and so forth.

But on to the field of history itself and how we arrive at the conclusion of something having veracity or not: In order to establish something as factual historians will use the historical method, meaning source criticism and a convergence of evidence. Those two go hand in hand and work like this: With any given source, we always evaluate them within the context of other sources and within its own context, meaning we check if it is internally consistent, if it matches in style, content and authorship with similar sources from the same time period and where it originated from and how it got where it is today. No source can ever really stand for itself but in an academic setting, it is a whole host of different sources, by different people, created independently of another that will serve as the basis for any claim for something being factual. That William the Conqueror arrived in Britain in 1066 is something established not from one document that says "And in 1066 William the Conqueror arrived in Britain" but something established from a whole host of chronicles written independently from one another, dated artifacts that do not appear earlier than that year, and so on and so forth.

It's rather obvious from this description that often it can be necessary to study history for quite some time to be effectively able to do that, I mean there is a reason why people spend 10+ years of reading in order to become a PhD when you are really able to say that in your specific area of expertise you have such a grasp to be really effectively able to do that. It is necessary to read a lot of sources and literature in order to be able to fully grasp the context in which you then can evaluate sources. But, again, this is true for almost any discipline and the reason why we have experts in things: So that we can rely on them having done their work properly and having been evaluated properly by other experts when it is time for us to judge certain claims – and this is not just true for the layperson but also fro trained historians – we too have to rely on other historians and their work in order for ourselves to do our own because it would simply be impossible to do everything from scratch for one person.

And this brings us to the first step of what any layperson can do when evaluating a historical claim: By asking the question where and from whom does it originate from. Sometimes, this is easy, e.g. when Hitler claims that the Jews stabbed Germany in the back we can safely say that Hitler, a man famous in world history for his anti-Semitic delusions of Jewish conspiracy, will make claims that are not true. Other times, this can be a bit more difficult but when someone cites a book as their source for a claim, some things are easy to check: Is the author a real historian or academic with a related degree? Is the book published with an academic publisher that does peer review? Can google books show me that the author uses footnotes and citations? What do book reviews on publicly accessible sites like H-net tell me about the book? For a quick even, what does wikipedia tell me and what sources do they cite?

Say, someone on reddit tells you that there was no historical Jesus and you want to check out that specific claim. You take to google as your first address and find the wikipedia page for "historical Jesus". There it says "Virtually all scholars who write on the subject agree that Jesus existed", which has four footnotes attached to it:

• In a 2011 review of the state of modern scholarship, Bart Ehrman (a secular agnostic) wrote: "He certainly existed, as virtually every competent scholar of antiquity, Christian or non-Christian, agrees" B. Ehrman, 2011 Forged : writing in the name of God ISBN 978-0-06-207863-6. p. 285

• Robert M. Price (an atheist who denies the existence of Jesus) agrees that this perspective runs against the views of the majority of scholars: Robert M. Price "Jesus at the Vanishing Point" in The Historical Jesus: Five Views edited by James K. Beilby & Paul Rhodes Eddy, 2009 InterVarsity, ISBN 028106329X p. 61

• Michael Grant (a classicist) states that "In recent years, 'no serious scholar has ventured to postulate the non historicity of Jesus' or at any rate very few, and they have not succeeded in disposing of the much stronger, indeed very abundant, evidence to the contrary." in Jesus: An Historian's Review of the Gospels by Michael Grant 2004 ISBN 1898799881 p. 200

• Richard A. Burridge states: "There are those who argue that Jesus is a figment of the Church’s imagination, that there never was a Jesus at all. I have to say that I do not know any respectable critical scholar who says that anymore." in Jesus Now and Then by Richard A. Burridge and Graham Gould (Apr 1, 2004) ISBN 0802809774 p. 34

Being so helpful as to include the positions of these people, we now have Ehrman, Grant, and Burridge tell us that virtually all of scholarship agrees on the historical existence of a person named Jesus, that might have had little to do with the Jesus known from the gospels but was still a historical person and we have Price who disputes the existance but still acknowledges that he is alone in these claims.

That alone can give one a pretty good impression of the veracity of a claim. You can certainly check the papers further as well as see who Erhman, Grant, Burridge an Price are and given all that information, you can surmise that people who put in a lot of time and study – who are experts with years of training – all more or less agree Jesus as a historical person existed. At least, you know that Price is standing alone and therefore his claims are to be enjoyed with caution and certainly not taken as absolute truth.

This is but one way for a layperson to check the initial veracity of some claims. For other interpretations it will be necessary to employ such critical skills as well as do some reading but it hopefully gives you an impression that a.) history is checkable and b.) a layperson can also go an check historical claims if they want to put the time in.

Read peer reviewed academic article's and books. No good historian is going to print something that is academically unsound. That excludes reddit and most popular history publications, if you want good history read stuff that is taught in universities with hundreds if not thousands of references at the end of the book.

The most sure way would be to check the facts yourself. It means archeological proof, documental reading, demographic quantification, etc..

The reason why historians trust papers and bibliography so much is because even a simple empirical contestation can take a lot of time, money and effort to wield results.

In short, the way you check historical facts is similar to how you check things in other sciences: get your hands on the field and ask not those who study it, but the world itself (with the downside that you can't replicate experiments and has to work with clues. It's like a detective's work).