Livy we have already seen had a historical method- he was to some extent a professional historian as far as we can tell. It is worth us trying to understand what Livy's approach to history consisted of. History in the ancient world was often a matter of observation- contemporary history being favoured over what we might call history today- the understanding of events long finished with. Livy of course studied our kind of history and therefore had to understand events in the far distant past. We have seen that Livy used conjectural history as a tool to understand events of the past but it is worth thinking about what else he did in order to form his narratives.
Livy relied as well on the accounts of previous Roman historians. The probability is that they themselves relied upon Roman family and public records, histories from the Greek colonies in the south of Italy and their own predecessors as Roman historians. Occasionally Livy names these predecessors- most of whose work is now lost to us- and therefore allows us to ascertain what his approach to them was. Take for example this passage from Book 3 concerning the campaign against the Aequians who had raided Rome:
In describing events so distant in time, it is difficult to make a precise or trustworthy estimate of the size of the forces engaged or the number of casualties: none the less Valerius of Antium does venture to do so; according to his account Roman losses in the territory of the Hernici amounted to 5,200 killed and those of the Aequian raiders in their engagement with Postumius to 2,400, the rest of them, who fell into Quinctius's trap as they were on their way home with their plunder fared worse, losing no fewer (as Valerius says with punctilious exactitude than 4,230 men (III 5)
There are a couple of things to note here- firstly that Livy was aware of the problem of talking in detail about events in the distant past. Secondly that he used his sources with scepticism- we are warned twice about the accuracy of Valerius of Antium's estimate- firstly in the overall warning about estimates and secondly in the language "none the less", "punctilious exactitude" with which Livy describes Valerius's estimate. Livy's own historical technique appears sceptical of the details of previous approaches- in this case exactly in the way that a modern historian would be. Livy like a modern historian understands that too much detail gives a hint of plausibility but also suggests an elaboration precisely because it is punctiliously exact.
We cannot deny that Livy did not use his sources the way a modern historian would- but we have to understand why. Firstly he did not have access to archaeology and the ability of historians today to reconstruct say the life of Etruscan Rome from the buried remnants of its ancient inhabitants. Secondly he believed that people in general behaved similarly in different epochs- not for Livy the conception of changing worlds of ideas- for him the lessons of ancient Rome were fully applicable in modern Rome but the opposite was also true: the social conflict of the 5th Century BC might be reconstituted from the social conflicts of the 1st Century BC. Livy has his limits in our eyes as a historian- but we ought to also acknowledge his strengths- he was not completely credulous about his sources. They may have vanished but we can see here his scepticism- he also was aware that there were limitations on his knowledge of the darkest corners of Roman history.