diff --git a/src/rules.jl b/src/rules.jl
index 05100e3..e1a1726 100644
--- a/src/rules.jl
+++ b/src/rules.jl
@@ -67,7 +67,6 @@
 @define_diffrule SpecialFunctions.loggamma(x) =
     :(  SpecialFunctions.digamma($x)  )
 
-@define_diffrule Base.identity(x)             = :(  1                                  )
 @define_diffrule Base.conj(x)                 = :(  1                                  )
 @define_diffrule Base.adjoint(x)              = :(  1                                  )
 @define_diffrule Base.transpose(x)            = :(  1                                  )