Ayah 18 - Deaf, Dumb and Blind

Sahih International

Deaf, dumb and blind - so they will not return [to the right path].
 

 This ayah gives characteristics pertaining to the hypocrites; that they are deaf, dumb and blind. But of course, this odes not have a physical interpretation, rather spiritual.
Deaf: They cannot hear guidance, nor comprehend it, nor have an open mind to it.
Dumb: They are unable to utter words that are of beneift to them or to others.
Blind: They are in total darkness and deviation (from the straight path). 

 

This is further elaborated on in Surah Hajj (22), ayah 46:

 So have they not traveled through the earth and have hearts by which to reason and ears by which to hear? For indeed, it is not eyes that are blinded, but blinded are the hearts which are within the breasts.

 

 And this why they cannot get back to the state of guidance that they were in, since they are unable to sense it. We are given 5 senses, which help us to "sense" the world around us, and perceive our surroundings. Without them, we are plunged into darkness, unable to communicate and make connections with our world. This is similar to hypocrites and the guidance of the heart. 

~A.A.