Full Idea
The Lambda Abstraction Operator: We can write (λx)[Man x], which may be read as 'the property that any x has just if x is a man'.
Gist of Idea
(λx)[Man x] means 'the property x has iff x is a man'.
Source
David Wiggins (Sameness and Substance Renewed [2001], 4.2)
Book Reference
Wiggins,David: 'Sameness and Substance Renewed' [CUP 2001], p.113
A Reaction
This technical device seems to be a commonplace in modern metaphysical discussions. I'm assuming it can be used to discuss properties without venturing into second-order logic. Presumably we could call the property here 'humanity'.