We tend to think of intelligence as something that describes just one individual. But it's possible to describe all kinds of collectives as intelligent, too – whether we're talking about social groups of humans, enclaves of insects, or even the mysterious behavior of slime mold and viruses.
By extension, could intelligence be observed on a much grander scale – perhaps that of an entire planet? In a newly published paper, a team of space scientists explores this tantalizing question, reaching some surprising conclusions about our very own Earth.
"An open question is whether or not intelligence can operate at the planetary scale, and if so, how a transition to planetary-scale intelligence might occur and whether or not it has already occurred or is on our near-term horizon," the team writes.
They note that understanding this question could help us to steer the future of our planet; however, according to their own criteria, it looks like we're not there yet.
"We don't yet have the ability to communally respond in the best interests of the planet," says astrophysicist Adam Frank from the University of Rochester.
"There is intelligence on Earth, but there isn't planetary intelligence."
According to the researchers, the emergence of technological intelligence on a planet – a common reference point in astrobiology research – should perhaps be viewed not as something that happens on a planet but to a planet.
In such an interpretation, the evolution of planetary intelligence would represent the acquisition and application of a collective body of knowledge operating across a complex system of different species at the same time, and in a harmonious way that benefits or sustains the whole biosphere.
Unfortunately – and obviously – humans and Earth are not at that point yet.
In fact, Frank and his co-authors say we've only made it to the third stage of their hypothetical timeline for the development of planetary intelligence.
In the first stage, characteristic of a very early Earth, a planet with an 'immature biosphere' develops life, but there are insufficient feedback loops between life and geophysical processes for co-evolution of different kinds of life.
In the second stage, the 'mature biosphere' has developed.
Next, a planet could become the third stage: an 'immature technosphere', where Earth currently is. In this stage, technological activity has developed on the planet, but it's not yet sustainably integrated with other systems, such as the physical environment.
If those tensions can be resolved, however, an immature technosphere stands a chance to develop to the final stage: the 'mature technosphere', where feedback loops between technological activity and other biogeochemical and biogeophysical states act in sync to ensure maximum stability and productivity of the full system.
This idealized state is where Earth should be trying to get to, the researchers argue.
"Planets evolve through immature and mature stages, and planetary intelligence is indicative of when you get to a mature planet," says Frank.
"The million-dollar question is figuring out what planetary intelligence looks like and means for us in practice because we don't know how to move to a mature technosphere yet."
According to the researchers, we currently sit on a precipice, where our collective actions clearly have global consequences, but we are not yet in control of those consequences.
If, in tandem with other forces on the planet, we can develop a balance where those consequences become controlled, we might finally evolve – as a planet – to the next level.
"A transition to planetary intelligence, as we described here, would have the hallmark property of intelligence operating at a planetary scale," the researchers write in their paper.
"Such planetary intelligence would be capable of steering the future evolution of Earth, acting in concert with planetary systems and guided by a deep understanding of such systems."
The paper was published in the International Journal of Astrobiology.