The Bootstrap Window Hypothesis: Why concentrated energy, not catastrophe, may be the great filter

Solutions to the Fermi paradox tend to fail in one of two ways: they invoke a filter without naming a mechanism, or they name a mechanism that no plausible civilization would fail to foresee. This paper advances the bootstrap window hypothesis, which names a mechanism and explains why foresight is not sufficient to escape it. The argument turns on a distinction between energy stocks and energy flux. A planetary system's flux is enormous and effectively permanent, but it is dilute, and capturing it requires capital infrastructure. That infrastructure can only be built out of the concentrated stock a biosphere accumulates over geological time. The stock is therefore not merely a resource but a bootstrap: the single, non-renewable grant of surplus with which a civilization must purchase permanent access to everything else. Because stocks are extracted best-first, the surplus available to spend on that purchase rises and then falls, opening a bounded bootstrap window. Civilizations that fail to convert the window into durable off-world capability are not destroyed; they are stranded at a level of complexity that produces no detectable technosignature. This reframes the Great Silence as neither the rarity of life nor the routine self-destruction of technological species, but as the expected consequence of a one-time energetic grant that is easy to spend and impossible to reissue. The paper states the hypothesis formally, distinguishes it from the closest prior work, specifies the conditions under which it would be false, and answers the strongest objections against it, including the argument that no filter is required at all.