Original Source: The Tails Coming Apart As Metaphor For Life | Slate Star Codex

What is the author's primary thesis?

In our study of morality, many systems of morality can reasonably agree on ordinary scenarios, but diverge greatly and fail completely when considering extreme scenarios.

What are the primary reasons given in support of the thesis?

For most ordinary scenarios, different schools (Catholic, utilitarian, etc.) will agree on ethical questions ("the morality of Mediocristan is mostly uncontroversial"), because our moral intuitions have been trained on the same data ("All moral systems were trained on the same set of mediocrestani data"). However, when considering extreme scenarios, like a post-singularity world, or one that includes transhumanism, our concept of morality itself can break down ("any moral rule followed to infinity will diverge from large parts of what we mean by morality").

What key terms and distinctions are used in stating the reasons?

a) Mediocrestani -- from Taleb; within the domain of the expected and ordinary. See Taleb's Concepts of Mediocristan and Extremistan

What central examples are used to illustrate the argument?

Mediocrestani:

• Starting a Catholic hospital
• Stealing from the pool

Extremistan:

• 1000-year reign of Christ and all non-believers go to hell
• The mass of the universe is covered by euphoric nervous tissue