In Deep Past (Rosetta, May), science writer Linden postulates that there were intelligent animals long before humans.

How likely is it that there has been intelligent life before our time?

I’d say that it’s likely that some ancient creature developed abilities analogous to human language and quantitative reasoning. It took a few billion years of evolution before any creature appeared that had anything like a brain, and even in our case, there was a period of several million years to lay the groundwork before our ancestors began a great leap in brainpower several hundred thousand years ago. But land animals and sea creatures have been around for several hundred million years, adapting to myriad environmental stresses. That creates a broad palette for evolutionary experimentation.

What’s the best evidence for that?

The best evidence is probabilistic and circumstantial: some degree of intelligence seems to be much more widely shared among species than previously believed, which implies that it has proven useful as an adaptive strategy. As the late scientist Donald Griffen stated, it’s probably more efficient for nature to endow a creature with some ability to make decisions than to hardwire it for every eventuality.

What guidelines did you employ in going beyond what is established science?

The ideas about the nature of intelligence and its evolution are grounded in established science or defensible theory. The ancient intelligent creatures are entirely my invention, but I tried to hew to plausible divergences from the paleontological record. My lead, anthropologist Claire Knowland, tries to adhere to scientific procedures even as she’s forced to cut corners to keep the discovery out of grasping hands. She must find a way to publish her discovery so that it doesn’t get dismissed as fringe science. I wanted to make the point that it’s not what you discover, but who believes you that determines whether a discovery or breakthrough sees the light of day.

Can you expand on the notion of intelligence as an adaptive strategy?

The simplest way to understand this is to think about the advantage of consciousness in complex social groups. If you can understand what other people are thinking, you can manipulate them or deceive them. That’s called metacognition. Its acme is Machiavellian thinking, and we now know that there are many would-be Machiavellis in the animal world. As for symbolic and quantitative abilities, if you can test out various strategies by building models in your head and choosing the best one, that’s a lot safer than testing out those strategies in the world.