At first sight it looked like an April Fools' joke. A branch of the US intelligence service called the Intelligence Advanced Research Projects Activity (IARPA) announced that it would be pouring millions of dollars into a "Metaphor Programme". "Perhaps it's a red herring," observed a colleague, entering into the spirit of the thing. But then we remembered that the US intelligence establishment doesn't do jokes, on account of it comprising lots of smart folks whose sense of humour was surgically removed at birth. So I read on.

"The Metaphor Programme," said the solicitation (ie call for research proposals) from IARPA's Office of Incisive Analysis (I am not making this up), "will exploit the fact that metaphors are pervasive in everyday talk and reveal the underlying beliefs and worldviews of members of a culture. In the first phase of the two-phase programme, performers [IARPA's intriguing term for researchers] will develop automated tools and techniques for recognising, defining and categorising linguistic metaphors associated with target concepts and found in large amounts of native-language text."

Ah! So it's computational linguistics on steroids. But why would US spooks suddenly develop an interest in an area that has hitherto been the preserve of humanities scholars? The answer has to be that they now hoover up every digital communication across thye globe, but lack the capacity to extract meaningful information from the resulting torrent of data. Given the scale of that torrent, the only way to analyse it is by using computers. The problem is that while computers are good at processing data, they're hopeless at understanding it.

Which is where metaphor comes in. The spooks' conjecture is that understanding how humans use metaphors might provide an efficient way of extracting meanings from messages. So the project's goal, says its programme manager, Heather McCallum-Bayliss, is to "exploit the use of metaphorical language to gain insights into underlying cultural beliefs by developing and applying a methodology that automates the analysis of metaphorical language".

Dr McCallum-Bayliss's presentation explaining the project makes fascinating reading. "Understanding the shared concepts and patterned behaviours of a culture is a significant challenge," she writes, "because cultural norms tend to be hidden. Even cultural natives have difficulty defining them. Having a system that could discover and structure cultural beliefs and perspectives would be valuable to novice and seasoned analysts alike."

An intelligence analyst, it seems, "needs to know the worldviews of the various cultures that she deals with. She presents a cross-cultural problem to the Metaphorical Language Analysis System to gain an understanding of the contrasting perspectives of the parties involved. The system offers two capabilities to the analyst. One will show cultural contrasts in the metaphors used for abstract and social concepts: Life is a Game vs. Life is a Struggle. The second will present a structured representation of the metaphors that expose insight into the views and goals of the protagonists in the situation."

Analysis of McCallum-Bayliss's presentation suggests that it owes much to Metaphors We Live By, a celebrated book by George Lakoff, a linguist, and Mark Johnson, a philosopher, which argues that metaphor is not just a device of the poetic imagination but something that is pervasive in everyday life. Our ordinary conceptual system, the thing that determines how we think and act, is, they believe, "fundamentally metaphorical in nature".

The inference is that if you understand how people in different cultures use metaphor, then you will have gained insights into how they think, and how they view the world. In their book, Lakoff and Johnson demonstrate this by conventional linguistic analysis. The hunch that is driving the IARPA project is that it may be possible to automate this kind of analysis.

At this stage there's no way of knowing if the hunch will turn out to be a pipe dream or a potentially sinister reality.

What's interesting is that serious people are apparently willing to pour large amounts of money into exploring it. But its audacity fits well with IARPA's declared mission to invest in "high-risk/high-payoff research programmes that have the potential to provide our nation with an overwhelming intelligence advantage over future adversaries".

The agency says that it is determined "about taking real risk", that it is not looking for "quick wins", "low-hanging fruit" or "sure things" and that "failure is completely acceptable as long as "results are fully documented". Coming from a government organisation, this is fighting talk indeed.

But most of all, it supports the theory that there really is no such thing as "useless" knowledge.

The thought that their work might one day fuel the "war" on terror will have generations of literary scholars revolving in their graves. And that's a metaphor too.