It’s come up a few times, so let me state here for the record the origin of Freeman Dyson’s First Law of SETI Investigations:
Freeman Dyson’s First Law of #SETI Investigations:
Every search for alien civilizations should be planned to give interesting results even when no aliens are discovered.
— Jason Wright (@Astro_Wright) November 2, 2018
It’s from an email he sent me. We were discussing a paper of mine in anticipation of an outreach event we were planning:
and he remarked of the Ĝ strategy:
I am happy to see that your plan is consistent with the First Law of SETI investigations: every search for alien civilizations should be planned to give interesting results even when no aliens are discovered.
I asked permission to repeat this, and he agreed. It’s consistent with his general approach about SETI, searching for the physical limits of technology in a way that also generates ancillary science and makes minimal assumptions about agency.
I think Freeman himself means this as a counterpoint to radio or laser SETI, which has the benefit of working against low natural background but this apparent disadvantage that they are unlikely to discover new natural phenomena in the course of their searches. I think this perspective is often overstated—radio SETI is closely aligned with pulsar and FRB astrophysics, and generates great science along the way, and there are natural sources of very brief optical flashes, too.
[Edit: Frank Drake had the same sentiment in his overlooked 1965 paper here (first appearance of the Drake Equation, BTW:):
Our experience with Project Ozma showed that the constant acquisition of nothing but negative results can be discouraging. A scientist must have some flow of positive results, or his interest flags. Thus, any project aimed at the detection of intelligent extraterrestrial life should simultaneously conduct more conventional research. Perhaps time should be divided about equally between conventional research and the intelligent signal search. From our experience, this is the arrangement most likely to produce the quickest success.