It's a risky long shot that burns up money and might never, ever pay off. So is searching for intelligent creatures on unseen worlds worth the candle? After all, aren't there better ways to use our monies and technical talents than trying to find something that's only posited to exist: sentient beings in the dark depths of space?

This is a question that surfaces more often than dead fish. "Why should my precious dollars be used for SETI when there's so much suffering in the world?"

It deserves an answer.

To begin with, allow me to get a technical misunderstanding off the table. As many readers know, SETI is not paid for with your tax dollars. At least, not if you're in the United States (where most SETI is conducted). Since 1993, when Congress killed the NASA SETI program, the search for signals from other societies has been funded by private donations. To be candid, even before that date, the amount of tax that was SETI-bound was only about three cents per year per citizen. But let's not argue whether that was a heavy burden or not: the facts are, it's currently zero. If you don't want to contribute to SETI, then it costs you nothing.

That small truth hardly silences critics, however. They look at SETI donors, and wonder aloud why these folks don't write those checks for medical research, foreign aid, or other humanitarian programs. In other words, the critics' plea is that we put all our money where our collective mouths are.

Well, such a circumstance has never been the case, and never should be.

A cursory glance at history shows that, even when people are routinely dying of hunger in the streets, some fraction of any civilized nation's resources have gone to seeking new things, or creating new things. Donors and patrons will always spend some monies on activities that, when analyzed on the crassest, basest level is "useless for society." They do that for lots of reasons – burnishing their image, love of Bulgarian ballet, or maybe just a desire to save fresh-water otters. But that's beside the point: if you give money to the local heart association, maybe it's because you're thoroughly altruistic. Or perhaps, deep down, you figure it might help you or your family in the long run. Either way, it's a good thing from society's standpoint.

Yes, but isn't "good" relative? Shouldn't there be a cost-benefit calculation here? Shouldn't philanthropists opt for the most effective project, in terms of societal improvement? That may sound good, but even aside from issues of free will, that argument leads to a terminally murky battle on what's important and what isn't. And sometimes what's unimportant today can become very important tomorrow.

Consider some examples. In Italy at the start of the 17th century, Medici family members Ferdinand and Cosimo proffered a regular allowance to an ambitious academic from Padua, Galileo Galilei. The guy found spots on the Sun and moons around Jupiter. You could have bought some meals with that money instead. But Galileo's work turned our worldview upside down by showing that Copernicus was right. I'm glad he got the florins.

Two hundred years later, Emperor Joseph II of Austria ponied up some coins to fund Wolfgang Mozart. Was this a good idea? Mozart was just writing music, for goodness sake. You can't eat music (unless you're a goat). But I can feast on it, and I do.

Then there are SETI's analogs from the first years of the twentieth century: the multiple attempts to pierce the heart of Antarctica and reach the South Pole. The principal men who led these forays into the lethal landscape at the bottom of the world – Shackleton, Scott, and Amundsen – did so for approximately the same reasons that motivate anyone with ambition: career advancement, glory, adventure, or simply to prove that they had the right stuff in the white stuff. But we're not talking about their motivation: we're asking why anyone would fund these guys. All three had donations from individuals. James Caird, a wealthy Dundee jute manufacturer, gave Shackleton a hefty hunk of change; steel magnate William Beardmore funded Scott on his first expedition; and Lincoln Ellsworth, son of an American industrialist, wrote checks for Amundsen.

There's hardly any mystery about why these private citizens would send explorers to realms that offered only frostbite and a bit of national pride in return. Yes, they were in it for the image building – the celebrity that would rub off on them if their boys brought back the bacon (only Beardmore seems to have expected to make a profit.) But these sponsors, like their prot?g?s, were also driven by curiosity – an inherent interest in exploration, in learning about the unknown. They wanted to know what was out there. For these folks – people who couldn't breach the frontiers themselves – it was exploration by proxy.

So, and perhaps too obviously, it's not inevitably about financial return. But it's also not always about new cures, new products, or even the alleviation of suffering. As Richard Feynman once said about physics, "it's like sex. Sure, it may give some practical results. But that's not why we do it."

And really, I think the same is true of the quest to find a signal from the stars. Funders of SETI are not putting their boodle on the table for commercial or national advantage. They're not hoping we'll be able to proselytize the aliens, nor do they await an opportunity to beat their chests with satisfaction if we find them. And while there's always the possibility that we'll learn wonderful things from an interstellar transmission, SETI speaks to a quintessential human need even without that carrot – the quest to know. More to the point: to know how we fit in. What is our part in the enormous cultural tapestry that we suspect threads the star fields of the Galaxy?

Are we truly biologically or intellectually special? One radio whistle from the cosmos would answer that question. Even if a discovery deflates our egos, it's still something that would be incredibly interesting to know. Ignorance is not bliss – it's only ignorance. When Copernicus argued that our view of an Earth-centered universe was parochial and wrong, he cracked a door in a stuffy house. SETI could blow out every window in the place.

As technologist Paul Allen said while commissioning the first elements of the new telescope that bears his name, "I like to call SETI the longest of long shots. But if this array picks up a signal, that would be an amazing thing – a civilization-changing event."

Surely, that's worth the candle.

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