Very clear article. If nothing else the Drake Equation serves to demonstrate how statistics based on unsound assumptions generates absurd answers.

On a tangential question: I wonder if anyone has calculated the minimum plausible mass for a Dyson Sphere placed around a modest white dwarf sun? Assuming ultra-ultra-light materials and assuming near-magical heat resistance and near-magical physical resiliency to the various particles suns routinely eject at phenomenal velocities, my own guesstimate for a “Dyson Ribbon” (using carbon 12 as a proxy for this ultra-light techno-magic, and making reasonable assumptions about the total area and volume of the DS) is in the order of 6x10 to the power of 9 metric tonnes. One would hope that the total energy captured & regenerated by the such a ribbon over its working life would at least equal the total energy required to build and position it in the first place.. Creating a full Dyson Sphere would require many orders of magnitude more material and require many orders of magnitude more energy to construct, which would make the whole effort-yield equation even less favorable.