What does conscience as a capacity mean?

Many define conscience as the capacity to determine between right and wrong. This is to some extent a true definition, but we must remember that that capacity is so overclouded and warped by circumstances that we are more or less insane in regard to right and wrong. We are more or less distorted in our mental vision. Conscience is, nevertheless, at work beneath all the madness or error that overclouds our moral vision. 

Deep down in the recesses of the soul, the voice of conscience is ever crying for deliverance from the weight of sin and wretchedness that presses upon it. Sooner or later, it asserts its right to be heard.