Ethan's third principle emerged at dawn: *Observation is free until it isn't.*
He'd spent the night watching Aethon through the Engine's surface, tracking the spread of microbial mats across the shallows of its single continent. Simple cyanobacteria, photosynthesizing in waters rich with iron and sulfur. The same chemistry that had painted Earth's oceans rust-red three billion years ago.
He'd felt nothing. No drain, no warmth, no cost.
But when he leaned closer, trying to resolve individual cells, the darkness at the Engine's center pulsed once. A warning, perhaps. Or an invitation.
He pulled back and added to his notebook: *Scale matters. Details cost more than patterns.*
The tremor in his left hand had returned fully now, accompanied by a new stiffness in his right ankle. He walked to the kitchen with a slight limp and made coffee with the mechanical precision of someone refusing to acknowledge their body's betrayal.
The doorbell rang at 7:15 AM.
Maya stood on the porch with two paper bags from the bakery downtown. "You weren't answering texts," she said. "I brought brioche."
"I was working."
"At your dead grandfather's house. At dawn." She pushed past him into the hallway. "Show me what you found."
---
On Aethon, something had changed.
The microbial mats had begun to differentiate. Not through Ethan's intervention — he'd only watched, careful to maintain his observer's distance. But the mats near thermal vents had developed a second photosystem, harvesting light at different wavelengths. An adaptation that would let them dominate the shallows within a few million substrate-years.
Ethan watched it happen in compressed time, the Engine translating eons into hours. Maya stood beside him, her reflection ghostly in the disc's dark center.
"It's responding to selection pressure," she said. "The environment you created has rules. They're just... following them."
"Abel's rules," Ethan corrected. "He set the initial conditions. I'm just watching his experiment play out."
"Are you?" Maya pointed at the notebook on the desk, open to his principles. "You touched it. You felt it respond. That's not passive observation."
Ethan said nothing. On Aethon, a mat near the continental shelf had begun producing oxygen faster than the ocean could absorb it. In another few hundred thousand years, the atmosphere would shift. Rust would give way to blue.
"What happens when you do more than watch?" Maya asked.
"I don't know yet."
"But you're going to find out."
It wasn't a question.
---
That afternoon, Ethan broke his fourth principle before he'd finished writing it.
He'd been tracking a particularly dense mat colony in a shallow bay, watching it spread across the substrate floor in fractal patterns. Beautiful, in the cold way equations were beautiful. Then he noticed the pattern stuttering at its edge, as though something in the substrate chemistry was poisoning its growth.
He leaned closer, trying to resolve the chemistry. The Engine warmed beneath his palm.
*Don't,* he thought. *Just observe.*
But his training betrayed him. Thirty years of solving problems, of seeing broken systems and calculating fixes. The mat needed trace copper to complete its photosynthetic cycle. The substrate soil had iron, manganese, zinc — but copper concentrations were three orders of magnitude too low.
He didn't decide to act. His mind simply ran the numbers: a volcanic vent, already present two kilometers east, needed only a slight shift in magma composition to leach copper into the water table. A nudge. A parameter adjustment.
The Engine pulsed.
Ethan felt the cost immediately — not pain, but *absence*. As if someone had extracted several hours from his lifespan and burned them for fuel. His vision grayed at the edges. The tremor in his hand intensified to a shake.
On Aethon, the vent began releasing copper-rich minerals.
The mat colony resumed its fractal spread.
Maya grabbed his shoulder. "Ethan. *Ethan.* What did you do?"
He steadied himself against the desk, breathing carefully. The gray faded. The shake diminished to its baseline tremor.
"I adjusted a parameter," he said. "One variable. The system was incomplete."
"You *intervened*. In an evolving ecosystem." She was staring at the Engine now, at the darkness that had deepened at its center. "That's not observation. That's—"
"Gardening," Ethan finished. "Abel did it too. Had to. You can't seed a world and walk away. Life needs... calibration."
"Life needed nothing. It was already evolving."
"Poorly."
The word hung between them. Maya stepped back, and Ethan saw himself reflected in her expression: a man at a desk, hands on a warm disc, watching microscopic life bloom in response to his choices.
Playing god.
Or becoming one.
"I should go," Maya said quietly.
Ethan didn't stop her. He turned back to the Engine and watched the copper-fed mats spread across Aethon's shallows, painting the substrate floor in shades of green and gold.
In his notebook, he wrote his fifth principle with a hand that shook: *Every choice is a theft from yourself.*
The darkness at the Engine's center had grown deeper. When he looked into it now, he could almost see something looking back.