# "Darwin Devolves" Ch 1: The Pretense of Knowledge

**URL:** https://discourse.peacefulscience.org/t/darwin-devolves-ch-1-the-pretense-of-knowledge/4102
**Category:** Side Conversation
**Tags:** Design, BookClub
**Created:** [January 27, 2019, 11:23pm UTC](https://discourse.peacefulscience.org/t/darwin-devolves-ch-1-the-pretense-of-knowledge/4102 "2019-01-27T23:23:28Z")
**Posts on this page:** 1
**Showing post:** 97

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### Author: ![T\_aquaticus](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/t_aquaticus/32/1249_2.png) [@T\_aquaticus](https://discourse.peacefulscience.org/u/T_aquaticus)
#### Post date: [February 1, 2019, 11:19pm UTC](https://discourse.peacefulscience.org/t/darwin-devolves-ch-1-the-pretense-of-knowledge/4102/97 "2019-02-01T23:19:40Z")

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> [@Mung](#):
>
> How is it selected against if it is not selected? And what is **purifying selection** , selection for purification or selection against purification?

Think of alcohol distillation. You purify the alcohol by leaving the water behind. The same applies to alleles where you select for the fitter alleles and leave the less fit alleles behind.

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