Is It A Mortal Sin If...

[twf]

For a grave sin to be mortal you have to understand the graveness, right? Well what if you know that, say lust, is grave but at the moment you commit the sin you aren't really consciously aware of the graveness. Is it still mortal?
Thanks,
God bless

[Adeodatus]

If you should murder someone (God forbid!), you don't have to be actively thinking, 'I'm murdering this person' as you kill them. If you generally know that murder is wrong, is a grave sin, then that counts as knowledge of gravity of sin. Few people think about gravity when they commit the actual sin, e.g. a man committing adultery may actually be thinking about what fun he's having at the time, rather than 'Oh look, I'm committing adultery'. That doesn't let him off the hook.

So that's two conditions for a sin to be mortal: 1. grave matter and 2. knowledge. The third thing is full consent of the will. Few people commit adultery through lack of consent, i.e. adultery is not the sort of thing that tends to happen to you by accident when you're walking down the street (not usually anyway). But the condition you mention, "at the moment you commit the sin you aren't really consciously aware of the graveness", may be a defect in the consent of the will---I doubt it, but I can't rule it out. In the heat of the moment, one may become confused about right and wrong because one is not attending to these things actively with the mind. One could still be guilty of deliberately putting oneself in such a position where the passions take over and the rational mind is hard pressed to set things straight.

In general, I'd say the situation you describe is of a faulty conscience, one that fails to work when it should, and acting on impulse on a weighty matter rather than through conscious deliberation using the conscience. That, in itself, if done through a lack of caring enough, suggests a lax moral attitude. Or it may reflect the fact that one is still growing up and maturing, and needs the grace of Christ in the sacraments and the Word of God to heal and to help.