Working with evidence：全部卡片

Who made it, when, and why

提示Before you trust a document, ask where it came from and whose hand produced it.

为什么Provenance is the backstory of the source. A diary kept on the day and a memoir dictated forty years later can describe the same event with very different reliability.

99 years

提示Careful at the join: the calendar jumps straight from 1 BC to AD 1 with nothing in between.

为什么Adding 50 and 50 gives 100, but there is no year 0: the sequence runs 2 BC, 1 BC, AD 1, AD 2. The count loses one year at the crossover, so the temple stood for 99. The same trap makes people say the twenty-first century began in 2000, when it began on 1 January 2001.

The third century BC

提示Same off-by-one trick as AD dates, but counting backwards from year 1.

为什么BC centuries are numbered outward from year 1: 1 BC back to 100 BC is the first century BC, 101 to 200 BC the second, and 201 to 300 BC the third. A larger BC number is always further in the past.

primary

提示Category depends on the question asked, not on the object itself; for a 2020s question the book is first-hand.

为什么Nothing is primary in the abstract; a source is primary for the question it sat inside. Cook's journal is primary for his voyage. A Victorian schoolbook is secondary for the Romans it describes, but primary for what Victorians wanted children to think about empire.

A secondary source

提示It was written long after the events, by someone drawing on other people's work.

为什么It repackages research done by others. It would count differently for a different question, though, such as how schools in the 2020s chose to teach the Tudors.

An inference

提示Reading between the lines: what a picture suggests, not what its caption states.

为什么A good one names the exact detail it rests on. Saying a family was wealthy because servants stand behind them in the photograph is an inference; saying they were wealthy on its own is only an assertion.

Street names

提示Tanner Row and Foundry Hill were not chosen at random; each one records a trade.

为什么Names like Shambles, Wharf Road or Colliery Lane preserve vanished trades. Old buildings, churches, war memorials and maps do the same job, which makes local history evidence you can walk to.

The diary

提示Memory fades and reshapes itself, whereas a record made on the spot has had no time to drift.

为什么Closeness in time usually helps accuracy, but not always: the man writing on the night saw only his own corner of the field, while the older writer may have learned the wider picture since.

Cross-referencing

提示Two accounts that agree independently give you far more confidence than one on its own.

为什么Where sources agree you can be more confident. Where they disagree you have found the interesting question: why would two people describe the same event so differently?

What its maker wanted people to believe

提示Even a lie is solid evidence of one thing: the aim behind telling it.

为什么Usefulness and reliability are separate tests. A government poster is unreliable about the facts of a battle but excellent evidence of the mood the government was trying to create.

To persuade people to think or act a certain way

提示It was not made to inform you; it was made to move you.

为什么Because it is designed to work on an audience, it shows what its makers feared and wanted. A wartime poster urging silence reveals a genuine official worry about careless talk.

Who collected them, and how

提示Numbers look neutral, but a person decided which cases counted and which did not.

为什么A census may miss people who avoided officials, and casualty lists may exclude civilians or the missing. Numbers deserve the same sharp questions you would ask of words.