I'm interested in having a better understanding of the different kinds of shoulds.
I believe it is more common to phrase the question using the term "ought". From an ordinary dictionary for the entry "ought":
Quote:Ought Definition | Definition of Ought at Dictionary.com
- (used to express duty or moral obligation): Every citizen ought to help.
- (used to express justice, moral rightness, or the like): He ought to be punished. You ought to be ashamed.
- (used to express propriety, appropriateness, etc.): You ought to be home early. We ought to bring her some flowers.
- (used to express probability or natural consequence): That ought to be our train now.
- duty or obligation.
Very often, philosophers distinguish between a practical or pragmatic version and moral or ethical version of "ought" (Kant expresses this as a difference between a hypothetical imperative and a categorical imperative) such as:
If you want to go to the store, then you ought to get into the car.
You ought to refrain from killing people randomly.
In the first, there is a goal that one has, and so the "ought" is simply about the means to achieve that goal (or end). This is a pragmatic sort of ought, which implies no moral or ethical obligation.
In the second, it is a typical claim in ethics, which is supposed to apply to everyone, regardless of their particular goals.
Looking at your examples:
If the law prohibits an action, then (generally speaking, at least) we shouldn't do what the law prohibits. We should, for the most part, obey the law. I guess we can call that the legal should.
What one would say about that will depend upon how one views the relationship between law and morality. But the way you have worded it ("We should, for the most part
[emphasis added], obey the law"), suggests that you are really discussing a moral ought, as it is not absolutely binding; if it were a "legal ought" (if there were such a thing), one would think that one ought to always obey the law, just as morally one ought to always do what is morally right. Of course, you might be discussing a practical ought, as it generally will get one more of what one wants to obey the law (as in, "if you want to stay out of prison, then you ought not commit crimes").
Your later post does not change this:
The evil judge looked down on me and was quite explicit when he said, "I don't care about what's right and wrong; I care only about what is legal and what is not." He judged that I should have done just what the law said, and my moral reasoning for what I done fell on deaf ears, as in his view, no moral reasoning would mitigate, let alone exculpate, me from my legal responsibility.
All I did was cross the double yellow line to keep from hitting the little girl that ran out in the street. I thought it was the right thing to do. I thought it was the moral thing to do. I thought that I did just as any reason person should do. But legally speaking, I should not have crossed the yellow line.
[all hypothetical by the way]
Should I have crossed the yellow line? Well, I suppose that depends on what is meant by "should." If we are talking about the moral should, then of course the answer is yes, but the word is ambiguous, and the speaker may not be using the word, "should" in the moral sense, and if the speaker is using the word in the legal sense, then the answer need not be the same.
For the law to function well, it must be that whatever action is punishable, is specified in law in advance. Thus, the question of whether or not a particular action is morally correct is not the issue when in a court of law being charged with something; that is an issue that is relevant to legislators making the law in the first place. In a court, the task is simpler: Did the person violate the law? If it is determined to be so, then the person is punished in accordance with the law, and if it is not determined to be so, then the person is let go. It would be ridiculous for a court to examine whether or not the law is as it should be in every case; every law would forever be up for grabs, without having consistency from one court to the next.
However, your specific example is inaccurate. You can cross a yellow line on some occasions, and if you have not run into anyone as a result, or caused anyone else to have an accident, avoiding running over a little girl is likely going to get you out of trouble for merely crossing over a painted line. Indeed, failing to try to avoid running over people, when it is possible to do so, is illegal in most places.
If a person is hurting from a very recent personal injury and is in need of help, and if we can help, then (barring ridiculous debate), we should, within reason, do what we can to help. I guess we can call that the moral good. Not doing so may be wrong.
That seems a fairly standard sort of example of a moral obligation.
If a gentleman holding boxes needs assistance opening a door, there may be no moral imperative to assist, (so, not doing so wouldn't be wrong, morally speaking), but doing so is still the right thing to do. We should help the man. I guess we can call that the good manners should.
I have never heard of anyone coming up with a "good manners should". But let us look a bit deeper: Why have good manners? I suspect that there will be lurking in the underbrush some morals in support of this, which will be less important than, say, a prohibition on killing him for no reason, but is still a moral ought. It seems to me to really be like your example of a moral should, where you are helping someone in need.
After weighing the advantages and disadvantages of each kind of roller coaster to add to our theme park, we decide, especially considering both costs and safety, that we should go with our first choice instead of the other choices. We should go with our first choice. I guess we can call that the decision should.
This seems like the practical or pragmatic ought. You think about what goals you have (saving money, being safe, etc.), and select the best means to achieve those goals.