The quote is rather similar in impact as the contemporary adage, "If you have to ask the price, then you can't afford it," and contains the same logical fallacy. Both wrongly assume that the questioner only and exclusively asks when the negative stipulation is true. Well, it isn't always true. Individuals who own $22 millions worth of success chain stores have been known to ask the price of hot spring spas and to choose the one offering unlimited all-day use for under $20 and rejecting the one offering one hour of use for over $20. Similarly, moral persons have been known to examine their consciences at every instance of moral choice. Therefore the quoted adage cannot be true since it--like the other--is predicated upon a logical fallacy.
I am often reminded of David Hume's comment that "reason is the slave of passion." Everyone has been placed in circumstances when ones best judgment and moral standards argue against that which one is about to do, or considers doing. I am also reminded of Paul's comments in Romans 7 when he speaks of the war raging in the members of his body, and in which he said,
the good I would do, I do not, the evil I would not do, that I do.
Moral dilemmas come to all of us. AS has been pointed out, our conscience normally tells us if something is wrong; but out human nature will still make us attempt to justify or "rationalize" it. So we may already know the answer; but we very easily convince ourselves that we do not.
"When it comes to matters of conscience, if you have to ask the question you already know the answer."
I disagree with the statement. For so many things, I think it is the primary function of our conscience to prompt us to question ourselves in the first place. Without asking those tough questions, we risk confidently milling about our lives, believing we are decent people who know right from wrong when we see it. That, in my opinion, is an oversight--it implies that morality and ethics are simple, which I don't believe they are. It might be more comfortable to assume that our first moral instinct is always correct, but that viewpoint neglects to acknowledge the manifold, varied, and even conflicting influences that made up the collective moral compass of our society. Those influences are confusing, and it's through self-questioning (with the "supervision" of our conscience) that we come to terms with our own true moral beliefs.
The conscience was made for wrestling with, and having that ability to think to one's self, "is this really ok?" means that we are continually forming and re-evaluating our sense of right and wrong. It means we care enough about humanity to question even our own judgment in the quest to do the right thing. A society where people feel they never need to ask themselves if what they're doing is right or wrong is a scary society to me, because it requires standardized, comprehensive moral dictates with no middle ground. And isn't that, in itself, immoral?
The fact that the act or issue raises a question of morality or immorality in someone's mind tends to suggest that it is immoral. Conscience is our sense of right and wrong, our guilt, and so when there is moral doubt at all, then it's probably best not to take the action. The quote is a guideline of sorts for settling matters of conscience in our minds.
To me, the saying means that we only ask ourselves if something is moral when we already know that it is not. When things are moral, we don't need to examine them. When they are not moral, we often tend to try to talk ourselves in to doing them anyway. We search our conscience, trying to find some way to justify doing something that we know we ought not to do.
Do I believe that this is true? That's a tough one. I know that there are times when I genuinely cannot decide what the right thing to do is. This happens a lot when I am trying to decide, for example, how much to interfere in my kids' lives and how much to just let them alone to make their own mistakes. But is that a matter of conscience?
Also, on matters that clearly are matters of conscience, are our "instincts" really based on what is truly right and moral or are they based on what has been drummed into us by our society. I remember being young and agonizing over what was acceptable in terms of what to do or not do with my (now) wife before we were married. Did I really know that doing x, y, or z was wrong or did I just think that because I was "brainwashed" by society?
So... very tough question!
I suppose this saying relates to the way that conscience is something instinctive within us and automatic. The process of asking and voicing the question about the moral dilemma we are in or are facing means that we have to confront what we instinctively know to be true and correct, and thus that makes our decision for us. With conscience, there is no wrestling or debating. We all know what our conscience tells us. The struggle is often whether to follow our conscience or go against it.