The long reflection is a hypothesized period of time during which humanity works out how best to realize its long-term potential.
Some effective altruists, including Toby Ord and William MacAskill, have argued that, if humanity succeeds in eliminating existential risk or reducing it to acceptable levels, it should not immediately embark on an ambitious and potentially irreversible project of arranging the universe's resources in accordance to its values, but ought instead to spend considerable time— "centuries (or more)";[1] "perhaps tens of thousands of years";[2] "thousands or millions of years";[3] "[p]erhaps... a million years"[4]—figuring out what is in fact of value. The long reflection may thus be seen as an intermediate stage in a rational long-term human developmental trajectory, following an initial stage of existential security when existential risk is drastically reduced and followed by a final stage when humanity's potential is fully realized.[1]
The idea of a long reflection has been criticized on the grounds that virtually eliminating all existential risk will almost certainly require taking a variety of large-scale, irreversible decisions—related to space colonization, global governance, cognitive enhancement, and so on—which are precisely the decisions meant to be discussed during the long reflection.[5][6] Since there are pervasive and inescapable tradeoffs between reducing existential risk and retaining moral option value, it may be argued that it does not make sense to frame humanity's long-term strategic picture as one consisting of two distinct stages, with one taking precedence over the other.