Full Idea
The fallacy of 'affirming the consequent' is of the form φ→ψ, ψ, so φ.
Gist of Idea
'Affirming the consequent' fallacy: φ→ψ, ψ, so φ
Source
Robert Hanna (Rationality and Logic [2006], 5.4)
Book Reference
Hanna,Robert: 'Rationality and Logic' [MIT 2006], p.141