Does the study of history have a different standard for truth than science?

There is no single standard of truth for "science" on the whole; physicists, biologists, ecologists, psychologists, etc., all have different expectations about how much "truth" they can access. As a general rule, the more complex the phenomena (where complexity doesn't mean "hard math" but "lots of different things interacting simultaneously") the more diminished is the confidence and sometimes aspirations for total mastery. So physics is extremely good at describing things that are simple by virtue of being small (e.g. elementary particles) and simple by virtue of being so massive that they can be generalized (e.g., stars and black holes), but has a very poor track record at being applied to understanding the workings of a cell, which requires a different sort of science (molecular biology). And psychologists, studying the complex interactions of the human brain (which is enormously complex just by itself) and the world that humans occupy (ridiculously complex) do their best, but it is no surprise that they appear to get it wrong quite often and have "revolutions" in their understanding every generation or so.

Historians, when views in this light, are studying about as "complex" phenomena as you can imagine: human beings, interacting in complex ways, with their world and all that it contains, over time. And they're doing it with one hand tied behind their back — they don't have access to more than a small amount of information about the past, and it is typically only certain types of information (e.g., government records are overrepresented, as opposed to, say, things that represent the inner lives of the governed or the governors).

So the goals are quite different. This doesn't mean the kind of knowledge that historians generate are entirely made up (they aren't; they are based on evidence) nor that they are useless (as narrative-driven creatures, this stuff matters for us and who we think we are — witness the recent controversies over statues). But any pretense of "scientific" understanding of history, or application of typical scientific methods (e.g., reductionism, simulation, laboratory isolation) to history tends not to work out well (it's all been tried). There is a mismatch between the kinds of knowledge those methods tend to be good at finding, and the kinds of knowledge that historians are looking to generate. (That is not to say that historians can't find scientific methods or insights useful — but those are always ancillary to the main goals of historians. They can help provide insights and structure, but they never give the whole story.)

The fact that historical knowledge is generally not subject to experimentation or testing (there are occasionally places where you can say, "if this was the case, I'd expect X to occur here," and see if that's true or not, but this is not really rigorously done) makes it very "un-scientific" as well. It does not mean that you cannot distinguish between better-justified historical narratives and others, in terms of the historical record. But it does mean that on many topics you will hit a stage in which the empirical, historical record justifies several different and competing interpretations, and there is no guidance on which (if any of them) is the correct one.

Good historians know this and own up to it; we don't pretend to be scientists, we don't pretend our understanding of the past is the "final" one, we don't worry that people in the future will see it differently. We do try to figure out what view of the past seems to make the most sense given the evidence and understanding we have, and our work as a profession is to sift through, offer up, and interpret such evidence.

In terms of how we evaluate evidence at all — how do you deal with a document, for example — that is through what we call "contextualization," which is to say, to look deeply, if we can, into the circumstances of the document's creation. We also look at the ways in which multiple documents make competing claims, and try to figure out what underlying reality might have produced those different documents and claims. We don't blindly believe everything that is written down. Sometimes there turns out to be very interesting historical narratives behind a given document and its wrongness (my favorite has to do with Soviet intelligence reports from WWII, some of which describe things that we are pretty sure did not happen — looking more deeply, one finds that if one was a Soviet intelligence officer stationed abroad and did not report ridiculous amounts of progress, one would get recalled to Moscow and vanish... so many of those field reports turn out, in retrospect, to look fabricated, because of how their intelligence-gathering system was set up).

I wouldn't necessarily regard this approach to "truth" as being a simple scale between "high" and "low," but different types of understandings. The kind of understanding that a physicist has of an electron is not the same sort of understanding that a historian seeks of, say, the end of World War II. It is an apples and oranges sort of comparison. Even the difference between how a physicist understands an electron and how a biologist understands a frog is not entirely comparable: every frog is an individual situated in time, and part of an evolving species, whereas you can very nearly regard all electrons as being identical (maybe even the same electron!).

This is not to say that every discipline is not connected — clearly you can weave an understanding of knowledge of the world at different scales of size and complexity across all domains of human understanding. But the type of understandings will differ in important ways.

There are also, I would note, many different types of historians as well, and different standards for evidence and historical interpretations in the different sub-types of history. A medievalist has a different approach to their work, and the past, than someone who studies the 20th century, for example, and when you start to blur the distinction between a historian and an archaeologist, all sorts of complex things arise. And there are approaches to history which put far more emphasis on complex interpretations ("theory") than they do empirical documents and evidence. So even generalizing for "history" is a big generalization.

(We won't, for the moment, get into how "truth" is really established in science — that is actually an entirely huge topic by itself, and one that historians of science like myself would be at pains to emphasize has itself changed over time. Suffice to say, "they have a proposition and they test it" is what scientists tell the public, and teach to school-children, but the actual operation of the scientific community is far more complicated and varied.)