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Single Idea 13367

[filed under theme 5. Theory of Logic / L. Paradox / 5. Paradoxes in Set Theory / e. Mirimanoff's paradox ]

Full Idea

Mirimanoff: φ(x) is 'x is well founded', so that w is the cumulative hierarchy of sets, V; &delta(x) is just the power set of x, P(x). If x⊆V, then V∈V and V∉V, since δ(V) is just V itself.

Gist of Idea

The next set up in the hierarchy of sets seems to be both a member and not a member of it

Source

Graham Priest (The Structure of Paradoxes of Self-Reference [1994], §2)

Book Ref

-: 'Mind' [-], p.27


The 8 ideas from 'The Structure of Paradoxes of Self-Reference'

The least ordinal greater than the set of all ordinals is both one of them and not one of them [Priest,G]
The next set up in the hierarchy of sets seems to be both a member and not a member of it [Priest,G]
The 'least indefinable ordinal' is defined by that very phrase [Priest,G]
'x is a natural number definable in less than 19 words' leads to contradiction [Priest,G]
By diagonalization we can define a real number that isn't in the definable set of reals [Priest,G]
If you know that a sentence is not one of the known sentences, you know its truth [Priest,G]
There are Liar Pairs, and Liar Chains, which fit the same pattern as the basic Liar [Priest,G]
Typically, paradoxes are dealt with by dividing them into two groups, but the division is wrong [Priest,G]