One could argue that the Roman war machine owed its success to various and diverse factors. However, one aspect that might pass unnoticed is its reflective deliberateness in planning and action. Let me contrast two passages that felt uncannily converging and that I want to share. The first one comes from Dewey ("How We Think") and the other comes from Josephus ("The War of the Jews" translated by William Whiston) who was an eyewitness from having fought the Romans as a general. Both Dewey and Josephus are great reads in their own right.
Dewey
from Part II ch.VII
Observation exists at the beginning and again at the end of the process: at the beginning, to determine more definitely and precisely the nature of the difficulty to be dealt with; at the end, to test the value of some hypothetically entertained conclusion. Between those two termini of observation, we find the more distinctively mental aspects of the entire thought-cycle: (i) inference, the suggestion of an explanation or solution; and (ii) reasoning, the development of the bearings and implications of the suggestion. Reasoning requires some experimental observation to confirm it, while experiment can be economically and fruitfully conducted only on the basis of an idea that has been tentatively developed by reasoning.
The disciplined, or logically trained, mind—the aim of the educative process—is the mind able to judge how far each of these steps needs to be carried in any particular situation. No cast-iron rules can be laid down. Each case has to be dealt with as it arises, on the basis of its importance and of the context in which it occurs. To take too much pains in one case is as foolish—as illogical—as to take too little in another. At one extreme, almost any conclusion that insures prompt and unified action may be better than any long delayed conclusion; while at the other, decision may have to be postponed for a long period—perhaps for a lifetime. The trained mind is the one that best grasps the degree of observation, forming of ideas, reasoning, and experimental testing required in any special case, and that profits the most, in future thinking, by mistakes made in the past. What is important is that the mind should be sensitive to problems and skilled in methods of attack and solution.
Josephus
Book III ch5
(concluding remarks about the Roman military organization)
This is the manner of the marching and resting of the Romans, as also these are the several sorts of weapons they use. But when they are to fight, they leave nothing without forecast, nor to be done off-hand, but counsel is ever first taken before any work is begun, and what hath been there resolved upon is put in execution presently; for which reason they seldom commit any errors; and if they have been mistaken at any time, they easily correct those mistakes. They also esteem any errors they commit upon taking counsel beforehand to be better than such rash success as is owing to fortune only; because such a fortuitous advantage tempts them to be inconsiderate, while consultation, though it may sometimes fail of success, hath this good in it, that it makes men more careful hereafter; but for the advantages that arise from chance, they are not owing to him that gains them; and as to what melancholy accidents happen unexpectedly, there is this comfort in them, that they had however taken the best consultations they could to prevent them.
7. Now they so manage their preparatory exercises of their weapons, that not the bodies of the soldiers only, but their souls may also become stronger: they are moreover hardened for war by fear; for their laws inflict capital punishments, not only for soldiers running away from the ranks, but for slothfulness and inactivity, though it be but in a lesser degree; as are their generals more severe than their laws, for they prevent any imputation of cruelty toward those under condemnation, by the great rewards they bestow on the valiant soldiers; and the readiness of obeying their commanders is so great, that it is very ornamental in peace; but when they come to a battle, the whole army is but one body, so well coupled together are their ranks, so sudden are their turnings about, so sharp their hearing as to what orders are given them, so quick their sight of the ensigns, and so nimble are their hands when they set to work; whereby it comes to pass that what they do is done quickly, and what they suffer they bear with the greatest patience. Nor can we find any examples where they have been conquered in battle, when they came to a close fight, either by the multitude of the enemies, or by their stratagems, or by the difficulties in the places they were in; no, nor by fortune neither, for their victories have been surer to them than fortune could have granted them. In a case, therefore, where counsel still goes before action, and where, after taking the best advice, that advice is followed by so active an army, what wonder is it that Euphrates on the east, the ocean on the west, the most fertile regions of Libya on the south, and the Danube and the Rhine on the north, are the limits of this empire? One might well say that the Roman possessions are not inferior to the Romans themselves.
