Zounds! It seems ideas really do matter in international politics and strategy. The South China Morning Post carried a long article last week confirming the influence Alfred Thayer Mahan now exercises in China. Someone should run with that topic—forthwith! Not that Chinese scholars or practitioners of a nautical bent are bashful about advertising their enthusiasm for Mahanian theory. America’s sea-power prophet has been a fixture in Chinese strategic discourses about the sea for at least a decade.

Indeed, The Economist’s pseudonymous Asia correspondent, Banyan, reports that a Mahanite leaps out these days whenever you poke a military man hailing from India or China. Mahan, it seems, proffers the trident to any nation that bears some resemblance to the America of his day—the natural hegemon on the rise that’s endowed with certain building blocks of sea power and covets a dominant say over events in its nautical near abroad. His influence is nothing new. Great powers on the make, including Imperial Germany and Imperial Japan, seized on Mahan’s writings during his lifetime, using them as a guide to constructing fleets and making strategy.

Strange to say, but the idea that ideas count is a contested one in the groves of academe. Many international-relations scholars voice discomfort at differences between states and societies. One of the deans of the realist school likens nation-states to billiard balls. His sports metaphor implies that nation-states are basically the same size and shape, have the same dimensions, and bounce off one another in regular, predictable ways. Right … that’s why IR scholars routinely and faultlessly foretell international interactions.

The mania for quantitative analysis that grips our field also helps explain scholars’ allergy to intangibles like strategic thought and human motives. How do you measure an idea? What units of measurement do you assign when forecasting the doings of governments or institutions? Better to measure what we can measure. Counting ships and aircraft or tallying up technical characteristics like ranges and payloads is straightforward relative to estimating how a different society—or, in the cases of India and China, a different civilization within a state—thinks about maritime endeavors and seeks its destiny on the wine-dark sea.

Give me decidedly non-quantitative scholars like Mahan’s contemporary Sir Julian Corbett any day. Sir Julian was fascinated with how navies had configured fleets and men-of-war over the centuries. Looking back as far as Henry VIII’s reign, he devoted inordinate attention to such intricacies as the evolving meaning of ship classifications like “battleship” and “cruiser.” Change didn’t arise solely from material factors like new propulsion or weapons technology. Corbett vouchsafes that “the classes of ships which constitute a fleet are, or ought to be, the expression in material of the strategical and tactical ideas that prevail at any given time.”

The make-up of ships and fleets, then, varies not just with “the material in vogue” but with how people think about amassing and using naval power. Even in the centuries before warriors and statesmen studied the profession of arms systematically, writes Corbett, “nebulous and intangible” theories about battle on the main “seem to have exerted an ascertainable influence on the constitution of fleets.” And indeed, it’s a comforting thought that seagoing powers don’t just build ships and armaments at random, then improvise tactics, operational methods, and strategy on the fly. They formulate ideas about what the nation needs to accomplish, then try to match forces to political and strategic goals.

So by all means, let’s keep track of the material dimension. No one disputes its importance. But let’s also bear in mind that bean-counting comprises only part of the strategic picture. A wise U.S. Air Force officer once proclaimed that people, ideas, and hardware—in that order—are the determinants of martial encounters between societies. Just so. Concentrating purely on one factor, to the exclusion of the others, begets myopia.