# The Problem of Induction

> 【EN】We generally think that the observations we make are able to justify some expectations or predictions about observations we have not yet made, as well as general claims that go beyond the observed. For example, the observation that bread of a certain appearance has thus far been nourishing seems to justify the expectation that the next similar piece of bread I eat will also be nourishing, as well as the claim that bread of this sort is generally nourishing. Such inferences from the observed to the unobserved, or to general laws, are known as “inductive inferences”. The original source of what has become known as the “problem of induction” is in Book 1, part iii, section 6 of A Treatise of Human Nature by David Hume, published in 1739 (Hume 1739). In 1748, Hume gave a shorter version of the argument in Section iv of An enquiry concerning human understanding (Hume 1748). … 【中】词条讨论归纳推理的辩护问题。我们的观察似乎能支持对未来的预测和普遍的规律，这种从已观察到未观察的推论即归纳推理。文章先重构休谟提出的难题，再依次考察规律—解释性方案、贝叶斯方案、各种局部辩护、组合性进路、否认存在归纳规则的立场，以及日常语言派的消解尝试。

- ID: m13223
- Category: culture
- Domain: 认识论

## Definition

归纳问题问的是：从已观察到的东西推出尚未观察到的东西，这种推理凭什么有效。看到某种面包一直有营养，似乎支持下一块也有营养；但这种从已观察到未观察的跳跃，既非演绎有效，也不能靠经验来证明而不陷入循环。 脚手架作用：- 预测审计：检查结论是否依赖未来如同过去这一未证前提。 - 循环识别：追问前提是否由结论本身推出，防止循环辩护。 - 类比评估：判断样本与推断对象是否同类，避免以偏概全。

## How it works

休谟的论证是：归纳推理依赖“自然齐一性”这一前提，而该前提本身既不能由演绎得出（其否定并不矛盾），也不能由归纳得出（那会循环论证）。于是归纳的正当性既非演绎的又非归纳的，我们实际上是在没有理性根据的情况下依靠习惯去推断。

## Practice

1) 把预测拆成已观察证据与待推结论，标出中间依赖的齐一性假设；2) 追问该假设的来源：演绎、归纳还是先验；3) 若无法给出非循环的来源，就把结论降级为有条件的，或改用贝叶斯思路看证据如何提高概率。

## Use

- 预测审计：检查结论是否依赖未来如同过去这一未证前提。 - 循环识别：追问前提是否由结论本身推出，防止循环辩护。 - 类比评估：判断样本与推断对象是否同类，避免以偏概全。

[Read the web page](https://thinkingmodels.site/en/entries/detail/m13223)