Editing New riddle of induction (section)

==Similar predicates used in philosophical analysis==

===Quus===
In his book ''[[Wittgenstein on Rules and Private Language]]'', [[Saul Kripke]] proposed a related argument that leads to skepticism about meaning rather than skepticism about induction, as part of his personal interpretation (nicknamed "[[Kripkenstein]]" by some<ref>John P. Burgess, Gideon Rosen (1999). ''A subject with no object: strategies for nominalistic interpretation of mathematics'', p. 53. {{ISBN|978-0-19-825012-8}}.</ref>) of the [[private language argument]]. He proposed a new form of addition, which he called ''quus'', which is identical with "+" in all cases except those in which either of the numbers added are equal to or greater than 57; in which case the answer would be 5, i.e.:

::<math>x\text{ quus }y= \begin{cases} x+y & \text{for }x,y <57 \\[12pt] 5 & \text{for } x\ge 57 \text{  or  } y\ge57 \end{cases} </math>

He then asks how, given certain obvious circumstances, anyone could know that previously when I thought I had meant "+", I had not actually meant ''quus''. Kripke then argues for an interpretation of [[Wittgenstein]] as holding that the meanings of words are not individually contained mental entities.