R.G. Collingwood, by whose philosophy of history Lonergan was greatly influenced, talks about something that he calls the historical imagination. The historical imagination functions not by taking ready-made statements found in sources and asking whether they happened or not. That's classic scissors-and-paste history, which Collingwood argues is not history at all. Ready it proceeds via inference, taking the sources as data. Let us illustrate via an instance from my family history.
I have a 1921 Canadian census record for the household of an Albert Bernier, age 36, living in Sherbrooke, Québec. I am confident that this is my great-grandfather. Why is that? Several pieces of information come together. I know through family oral tradition that my great-grandfather was named Albert Bernier. I know that my great-grandmother, his wife, was named Adelina. I know that my grandfather, his son, grew up in the Sherbrooke area. I know that my grandfather was born in 1922 and had three older siblings. I know their names: Elizabeth, Joseph, and Jean. I know that Elizabeth and Joseph were born in Waterbury, Connecticut, when my great-grandparents were residing there. I know further that my great-grandparents were from Québec, and only sojourned temporarily in Waterbury. So what I have in the census document is an Albert Bernier, living in Sherbrooke, with three children, Elizabeth, Joseph, and Jean, ages 3, 2, and 5 months; it tells me that he and his wife, Adelina, were born in Québec; it tells me further that Elizabeth and Joseph were born in the US but Jean in Québec; it fits. I could be mistaken, but there would have to be a lot of coincidences.
I have another document. It's a US draft registration form for an Albert Bernier, filled out in 1917--the year the US entered the First World War. It was filled out in Waterbury, Ct. It has him listed as age 32, the age my great-grandfather would have been if he was 36 in 1921. It indicates that he is married without children, like my great-grandfather would have been if his eldest child was three in 1921. It states that he is an alien from Québec. Quite probable, I think, that this is the same man.
Now, put it together this means that my great-grandfather was resident in the US in 1917 and still in 1919, when his second child was born. Between 1919 and the birth of his third child in 1921 he returned to Québec. Here is where my imagination really kicks in, although I've already in fact been using said faculty to make these connections between family oral tradition and these two documents. But now I ask the most important question: Why? Why did my great-grandparents move to Waterbury by 1917, and why did they move back in around 1920? I turn to the history of Québec and come up with a possible answer. The First World War, which Canada entered in 1914, was a deeply divisive war in French Canada. Many Québécois felt that it wasn't their fight and had little interest in joining up. As conscription became first a possibility and then a reality, many Québécois took steps to avoid being drafted. Since the US did not enter the war until 1917, I hypothesize the following: that my great-grandfather and his wife moved to Waterbury, Connecticut, where there was already a sizable Québécois population dating back to the 19th-century, in order to avoid the possibility of conscription. Then, when the US entered the war, with conscription a reality in both the US and Canada, he ended up having to register anyways. He was something that seems quite odd, in light of more recent experiences: a Canadian who moved to the US in order to dodge the draft.
This also helps explain another interesting bit of family history. When my grandfather joined up within days of Canada declaring war on Germany in 1939, his parents did not approve. This caused a deep rift with his family, one that never fully healed. It was only deepened when he decided to service out a career in Canada's post-war army, staying in the service until 1967. This rift makes perfect sense if his father had taken significant steps to avoid service in World War I. These were people who didn't like the idea of going to war.
At this point it is just a hypothesis. I would have to do more digging to confirm that this is what happened. But it does fit the data. It coheres remarkably well. It has explanatory power, pulling together a number of threads of my family's history that otherwise I find somewhat inexplicable. And what is interesting, from the perspective of a historical Jesus scholar, is that I have not a single source that says that my great-grandfather was a draft-dodger. It just all comes together to form a reasonable portrait, one developed with criteria or the like. Just simple old detective work. And really, I'm not sure why the study of early Christianity would be in principle any different.