But what of you have no conscience (i.e. psychopaths)? What if your conscience excludes the rest and has no regard for the world around you?
Our conscience is o guide. We will be wrong vis-a-vis what Christ taught if we follow our conscience because of pride.
If Christ is the light, the way and truth then it is not or conscience but Him that we need to follow always. But we don't.
I am assuming that you are thinking of a person who has no affect of "remorse". If one is a real live sho'' 'nuff psychopath, I think we have to consign that one to the mercy of God. Some organic thing went haywire or some traumata of early life really trashed the internal economy. And only God can amend it.
There's another disorder in the affective side of what we call "conscience" and that is the problem of feeling remorse when one has done nothing wrong. Some soldiers feel remorse, as do some parents, when in both cases they have done what is right but cause some kind of suffering to others.
I answer that
conscience, rightly so called, is the "practical reason" informed by the generally innate apprehension of moral law, natural law as applied to human type personnel.
Remorseful or satisfied affect is distinct from synderesis, I suggest. In this understanding, conscience does not spring full-grown from the infant brow, but is developed and enhanced, strengthened by the pursuit and practice of virtue, weakened by vice, and wonderfully informed not only by special revelation (who knew that two wives was one too many?) and by God's acting in the individual (come to think of it, I don't even WANT two wives -- one is quite enough!)
So saying "follow your conscience" is not saying, "If it feels right, it can't be wrong." HECK no! That is what we scholastics refer to as "the Country Music Heresy", and it leads to honky-tonks where the Pearl longnecks trash the affective and discriminative functions, and then to waking up in the beds of strangers.
So I wonder sometimes if one couldn't, assisted by grace and the careful but firm application of a two-by-four to the head, get a psychopath to (a)commit himself to Christ, and (b) work out in his head what right actions probably are, and (c) resign himself to acting w/o the encouragement and guidance of affect.
But for the rest of us, conscience must be developed by thinking, study, and the practice of virtues, and most of all by God's grace, besought in prayer and sacrament.
How'd I do?