The importance of dates in history

In her Uplifting Quotes for the Uninspired Historian series, the Resident Judge of Port Phillip had a short but interesting review (Uplifting Quotes for the Uninspired Historian #8) of Ged Martin's book, in Past Futures:  The Impossible Necessity of History, Toronto, Toronto University of Press, 2004. I haven't read the book yet, but wanted to pick up one point, the importance of dates.

Ged Martin wrote:

Every decision is a double decision, requiring us to ask first, ‘why when?’ and only then ‘why what?’. The operative second part is the action of saying ‘yes’ or ‘no’ to the available options.  The historical core is to be found in that crucial first part, the decision to take a decision.  We should begin by seeking to understand not simply why a decision was taken but when it was taken.  This helps us to appreciate why, at that time, some options but not others were available to those making the decision. (p. 93)

In the post modernist history world, there was a strong tendency to dismiss dates as unimportant. What was important were patterns and especially themes - women, aborigines, colonialism are examples. Yet you cannot understand history if you don't understand dates. Let me illustrate with a personal example.

When I was writing my PhD I drew from the work of a fellow historian to argue that the extension of the railway line north from Newcastle created an inland Northern economic commonwealth centred on Newcastle that was destroyed by predatory railway freight pricing once the railway connection went through from Newcastle to Sydney.

Now in broad terms that's right. Yet some of the conclusions I drew were at best suspect, at worst plain wrong. I found this out much later when, for another reason, I needed to check the dates at which parts of the Great Northern Railway opened. There simply wasn't enough time between those dates and the completion of the railway to Sydney to support the weight of the conclusions I was drawing.

I felt quite silly because I had allowed my analysis to outrun my evidence!