On the nature of history

This has been bugging me for a while. Now, bear with me, because I'm no expert on the subject, this is very much a layman question. And if you feel like this is a display of ignorance and you could deconstruct my reasoning in 2 minutes, by all means, please do. I wish to clarify my own thoughts on the matter.

Anyway, here's my issue : Why is history treated like an exact science? Why is there an established "canon" of history, when by its very nature, this discipline is highly speculative? Material evidence is scarce and incomplete, but the real problem lies in historical sources. How can we truly determine the accuracy of a source? We know that, even as far back as classical antiquity, governments were already practising disinformation, and even borderline Orwellian editing (Damnatio memoriae comes to mind). We don't know how many documents were altered, censored, or suppressed. I'm willing to bet that conquest often involved massive destruction or editing of the enemy's historical records. And human history is rife with conflict, one could almost say it revolves around conflict.

To put it in a more coherent way, here's my question :

How can people agree with these assertions :
1) "History was written by the victors"
2) "The classical sources are reliable"

...and not see an obvious contradiction?

reply to post by Cathcart

How can people agree with these assertions :

1) "History was written by the victors"
2) "The classical sources are reliable"

...and not see an obvious contradiction?

To understand the contradiction one must first use critical thinking. That's not something taught in many schools today (or yesterday for that matter.)

Once a person questions history it becomes a matter of researching whatever data is left and available. In my mind it almost becomes like archeology, a lot of dirty digging to find a shard. That said not all history should be considered false or rewritten.

A good example might be the Holocaust. While there are obvious agendas surrounding the "real" story it is possible to still talk to people who where there. For older history sometimes it may require multiple avenues of information that are cross referenced to get an idea of what really happened.

Unfortunately most people can't be bothered.