“I do not see why you can parallel—”

“Hear the end of the argument, at least.” She frowned at him and again wondered where all this was coming from. “Look at it!”—she swirled around, both arms out, sweeping the horizon. “Even with an atmosphere nearly fifty times the original thin skin of carbon dioxide, it’s barren! No isolation lab on Earth is remotely as hostile to organic chemistry. A terraformed Mars, filled with life—forests, farms, seas, playgrounds, used book stores, who knows what?—how can that not be a vastly richer gift to posterity?”

“That posterity will lack the Mars we know.” He looked around with distaste, and pointed to the gully. “Or knew.”

She had to admit, though only to herself, that the sharply eroded scar did resemble a wound. Some aspects of world-making were not pretty. “Look!” She whirled around again, feeling oddly giddy, impetuous. “Anybody who proposed changing our Earth into this place would be mad, mad, mad—and bad. So why doesn’t that logic work in reverse? Keeping Mars dead rather than make it as wonderful as Earth is—”

“Incorrect logic.” His lips compressed into a thin white line. “Arguments can’t run backward.”

“Maybe. But I can—!” She took off, running downhill, taking long strides in the relaxing 0.38 gravs. It felt good to switch off her comm and leave the dead argument behind her. Stefano hadn’t, so she heard his startled yelp and chugging breath as he ran downslope, too. A glance back told her Stefano couldn’t keep up; he seemed in poor shape.

She sped down the brown-red soil, placing her boots so she didn’t land on rocks, leaping small gullies, headed for the habitat. This was Mars, for Chrissake, an alien place, not just a debating point—and she intended to experience it, not argue it.

Too late, she thought of other arguments. Marsforming was a long-term project, and there would come the chance to see directly if and how the Mat adapted to warmer, wetter days. There were plenty of terrestrial microbes incoming from the occasional Earth knockoff rocks, and plenty more brought by humans. Native and immigrant life blending, showing how such past ages might have looked. Understanding of Martian biota would increase by terraforming, not decrease.

Microbial biospheres had survived the early bombardment days on both planets. Life, once started, seemed determined to last.

But Stefano wouldn’t care about arguments, really. Most firm positions came from emotion, not reason. What was that old law?

Passion is inversely proportional to the amount of real information available.

Too true, too true.

Back inside, Rachel showered twice and had a tiny glass of cognac––a minor breach of rules––to wash away Stefano and the dung job, rather similar experiences. As soon as she had water on for tea, she turned on some piano pieces by Chopin.

A little later, refreshed, she ambled into the habitat lounge. A big screen showed a newslink to Earth, with a reporter interviewing the oldest woman on the planet, just turned two hundred. He asked her, “And what do you think is the best thing about being two hundred?” Her lined but vigorous face split with a smile. “No peer pressure.”