What really confuses me is how we actually know it is 2014? If we don't know much about certain periods of time, like in British history between the fall of the Roman empire and the end of the dark ages, how can we be sure we've added up the dates right? I suppose more generally i'm skeptical about how much we actually know about history, and how we can trust very old documents and how much is made up to fill in the gaps. I imagine a scenario where a King/Queens wants to be remembered in a certain way, so pure fiction is produced, which would be indistinguishable from fact. If they wanted to they could even extend their rule (only in the history books), say, by however many years they wanted and no one would know.
I've not really had a massive interest in History precisely because of this reason - and I know that's not good (and want to change that), but I don't know where to start looking to answer it. Whenever I watch a history programme on TV or read a history book, I'm always left thing, "yeah but how do you actually know that, you sound so certain!" I hope my question makes sense.
The most definite way is by old astronomical records. We know down to the minute when all the eclipses, periodic comets, etc of history took place, so if there was an eclipse on a certain day of the reign of the emperor Claudius, we know what year that was. Thus we know that there are some years we don't know much about, but there are no missing years.
The other way is because historians can correlate between different places. So for example if a English monarch wanted to 'fake' years of his reign then documents in would have different dates for specific mutual events than counterparts in France, Spain, Italy etc.
Two other issues, while I can see some motivation to lie about ruling longer than one actually has, as a historian I can't imagine a king actually trying to put that into practice. The scale of the lie is just too big even in the medieval period there are still enough scribes-notaries around that you would have to get everyone on board and then the problem of neighboring kingdoms not matching your faked timeline is easily apparent - for example in a treaty or marriage contract.
I imagine a scenario where a King/Queens wants to be remembered in a certain way, so pure fiction is produced, which would be indistinguishable from fact.
As a historian this is actually one of the most interesting parts of studying history. First, there is no objective historical document, not one. Every document is produced by a particular author with a particular subjective view and intended for a particular audience. Historians must always consider the bias that exists. The flip side is that when in the past people thought to 'fake' a document, or to lie in a document, they had to do so in a way that retained the verisimilitude of the account. For example, I read a lot of inquisition cases, people lie there all the time, but it is not complete fabrication because that is too easy to spot or check. So, instead, people have to bend the truth and tell an alternative story that is plausible for their circumstances. Yet, the beauty of history is that because they have made the account plausible within their own cultural-historical moment it is a true statement in the sense that it could have happened and that they expected/hoped that it would be construed as fact. Thus, even a forged or fudged document tells us something about the past because the person who produced that document intended that it would appear real.
That type of analysis is more suited for studying socio-cultural phenomenon. In the case of political or economic history it is usually easy enough to determine if an account is faked/overly-biased by comparing it to many other documents. Again, historical conspiracies are unlikely, largely impossible to achieve, so a preponderance of correlating evidence usually indicates historical reality.
Vaguely related to this question, when did the Western world come to use the current year system? Like, when was it decided that 'this is the year x' that our current date is a continuation of?
This would be more a philosophical/epistemological question than a historical one.
History, like science, has a certain corpus of agreed upon assumptions that can and are disputed philosophically. For example, the sciences make an assumption that there is a "real world" that exists outside of observation and thought and can be alluded to. It makes the assumption that induction (the observation of repeatability of phenomena) is a valid means by which to theorize about laws of action. These can and are disputed philosophically.
Because if we're being honest here, it's quite easy to take your argument, philosophically, to its logical conclusion toward cartesian solipsism (do any of you or any phenomena exist, or you're just really fancy meat robots or illusions created by demons?)
It doesn't mean your argument is logically invalid, it's more that your argument isn't socially privileged by the scientific community (because it would paralyze the inductive scientific process).
You might want to consider trying /r/askphilosophy
In addition to the other well reasoned replies in this thread, you can also bet for sure that the Arabs, Chinese, Indians, Greeks, Persians, etc were all keeping track of time too! If someone wanted to fudge the date, historical analysis using multiple regional calendars would show who's lying.
We can also date artifacts radiologically. Carbon isn't the only thing we can use for this and, as a result, we can get a good macroscopic view of things.
One of the handier techniques in this regard is the ability to date construction materials. For example, we can date the concrete used to construct the Colosseum . Not surprisingly, the construction of a 50,000 seat mega-stadium in the middle of the capital of Iron Age Europe did not go unnoticed and so we have documents that discuss the Colosseum and other things as well.
As we know the age of the Colosseum we can extrapolate the dates of the other events as well.
It's best to look at several different methods of measuring time. Astronomical records (as mentioned in another comment) are one, and tend to be the most precise.
Radiocarbon dating is another. It can tell you when a particular dead thing was alive, e.g. when a tree was chopped down. If we were missing years in our chronology, then we'd end up with artifacts that were found to be younger than history records them to be.
But, how do we know that radiocarbon dating is correct? We calibrate it using my favorite method of determining age: dendrochronology (i.e. counting tree rings). We have records of tree rings spanning 8000 years. Carbon dating these types of samples ensures the accuracy of the method, independent from historical records.
There are other methods as well. For areas with recorded history, you can correlate reports of regional or global events to establish dates as well. Generally, multiple methods will converge on a specific year or at least a range of years. If one method disagrees, say wood in a monument is determined to be much older or younger than the otherwise established date for the monument, there's some explaining to do (was the wood recycled from an older structure or was the monument repaired at some point?). If we were missing years, dating methods would end up consistently disagreeing with each other.
I'm sure this has been said before but the study of history is EXACTLY dealing with the problems you've put forth. Considering ancient letters, documents, ledgers, etc., can be exciting in itself (minus ledgers) it's the real job of the historian to put them into context.
An example of the big questions a historian must consider; who wrote this? Is there any reason for bias or to manipulate information (for instance does it mention a tyrannical king/queen)? Is a first or second source? Why was it written? Is the author pushing an agenda or collecting taxes?
To be clear I'm an extreme amateur and do it more for fun, my opinion on first hand sources could be compared to pure guesswork. Regardless, the process is very engaging. Information has to be taken in the context of the period it was written in. Even subtleties like handwriting (I'm not a student nor am I interested in becoming one) are considered when dissecting a historical document. History could largely be compared to a mystery, where each clue may not be what it seems and large finds might change the entire school of thought on any subject.
This is a frequently asked question here. You may want to refer to these similar questions linked from the FAQ:
See this fascinating answer how dendrochronology can date things to the year.
And a related question that may interest you:
My old archaeology professor used the pace of evolution of Mesopotamian pottery to prove that the established calender of events in the ancient Middle East was a bit too spaciously timed, and a century or two were pruned as a result. So the calendar remains a hypothesis - albeit one with very little wriggle room in times with a lot of sources.