各种各样的(伪)自我指涉

数学上：能否实现在文件中保存文件自己的MD5值? - justjavac的回答 - 知乎
有没有可能二维码保存的图片就是这个二维码本身？ - 知乎
图像就是自身的不等式（塔珀自指公式）是怎么发现的？ - 知乎
是否存在一个字符串，它的md5值是其自身？

嗯，其实有些和自我指涉关系不大。。。
想到再补充

 
 
 

A quine is a computer program that takes no input and produces a copy of its own source code as its only output. The term "quine" is named after the American philosopher and logician Willard Van Orman Quine (1908–2000), whose work in logic and philosophy explored self-reference and related paradoxes. The connection between his ideas and self-replicating programs lies in the concept of self-reference, which is central to both his philosophical work and the behavior of quines in computing.

Why is it called a "quine"?

The name "quine" was introduced by Douglas Hofstadter in his 1979 book Gödel, Escher, Bach: An Eternal Golden Braid. Hofstadter named these programs after Willard Van Orman Quine because of Quine's interest in self-referential statements and his exploration of logical paradoxes, such as the "quotation paradox." For example, Quine's paradox involves statements like: "yields falsehood when preceded by its quotation" yields falsehood when preceded by its quotation. This paradox highlights the challenges of self-reference, a concept that is mirrored in the behavior of quine programs[2][9][13].

How does a quine work?

A quine program is designed to output its own source code without directly reading it from a file. This is achieved through clever use of programming constructs and the fixed-point theorem in computer science, which ensures that any Turing-complete programming language can produce such self-replicating programs. Writing a quine often involves embedding the program's structure within itself in a way that allows it to reproduce its own code[3][4][7].

Philosophical and computational significance

Quines are not just programming curiosities; they have deeper implications in both philosophy and computer science:

• Philosophy: Quines reflect the concept of self-reference, which is central to many logical paradoxes and Gödel's incompleteness theorems. Willard Van Orman Quine's work on self-referential statements inspired the naming of these programs[2][9].

• Computer Science: Quines demonstrate the power of recursion and self-replication in programming. They are also related to theoretical concepts like the Kleene recursion theorem, which formalizes how programs can access and manipulate their own code[6][7].

In summary, quines are named after Willard Van Orman Quine because of his contributions to the study of self-reference and logical paradoxes, which align with the self-replicating nature of these programs. Their creation is both a technical challenge and a philosophical exploration of self-representation.
[1] https://medium.com/the-modern-scientist/quines-a-fascinating-look-at-self-replicating-code-5f92a76cdddc
[2] https://crypto.stanford.edu/~blynn/lambda/quine.html
[3] http://www.madore.org/~david/computers/quine.html
[4] https://www.geeksforgeeks.org/quine-a-self-reproducing-program/
[5] https://www.ituonline.com/tech-definitions/what-is-a-quine-program/
[6] https://www.educative.io/blog/quines-self-replicating-programs
[7] https://en.wikipedia.org/wiki/Quine_(computing)
[8] https://riptidedata.medium.com/beyond-the-source-code-quines-and-self-replication-fab3e000696c
[9] https://en.wikipedia.org/wiki/Willard_Van_Orman_Quine
[10] https://discourse.haskell.org/t/self-replicating-code-quines-a-fun-exercise/8061
[11] https://substack.com/home/post/p-122479616?utm_campaign=post&utm_medium=web
[12] https://www.quora.com/What-are-Quines
[13] https://juliu.is/quine-quine/
[14] https://www.nyx.net/~gthompso/quine.htm
[15] https://iep.utm.edu/quine-sc/
[16] https://quine.io/info/about/
[17] https://www.reddit.com/r/linguistics/comments/lslq0i/a_natural_language_quine/

 
 
 

贴个埃舍尔的很著名的那幅画结尾吧