11. October 2019
Russell's Paradox
Back in 1902, mathematicians defined a set as follows:
A collection of distinct objects, where an object can be anything, including a set.
So, here are some sets under that definition:
{ 4, 5, 6 } { a, b, c, d } { 8, a, 🌍, “The concept of FOMO”, 🤔 }
But also:
A = { 0, 1, 2, A }
Where A is a set that has the element A, which is…itself.
For decades, mathematicians thought this was fine, until Bertrand Russell pointed out a paradox.