I see a lot of banter on Law SE, quoting at former cases.
I'm not sure what you mean by banter. If you mean answers and comments, this reflects the way judges in common law jurisdictions generally decide law - by quoting former cases, and, in general, following the principles, or the decisions. This is known as stare decisis, and supports the principle that the application of the law should be predictable.
More generally, however, these comments requesting clarification and proof reflect the process of peer review, which helps to ensure that users cannot make unqualified, unsupported answers.
I haven't seen any actual dialog starting from first principles of the Law, if this site has even or ever stated such.
I actually hope you haven't seen too much dialog at all. The primary purpose of this site is to answer questions. Dialog is necessary in some cases in order to clarify or object to an answer.
As for the first principles of law, questions about such are welcome. Answers should be supported by referenced principles appropriate to the relevant legal system. In some cases these principles will differ - in customary law, common law, and civil law there will be at time vastly differing jurisprudential principles.
Answers that cite references appropriate to the question apply more basic legal principles by proxy. However, in common law judges generally are not, except in the case of supreme courts, free to exercise absolute discretion and apply the most basic principles.
If it hasn't, then I suggest that the site stipulate what legal jurisdiction the questioner and the answer are interacting from.
There have been a number of discussions on the stipulation of jurisdiction. The general consensus is that specifying a jurisdiction is helpful, but not strictly required. Some reasons for this might be that some principles are similar across jurisdictions, some questions might want a more general answer, or that we want to encourage questions and set a reasonable bar for them.
What we expect to happen - and what does happen - is that users will ask for a jurisdiction, then, if they don't receive one, answer as if one had been specified (generally the answerer will select one they are familiar with), or if they do receive one, edit the jurisdiction into the tags, question and/or title.
Otherwise, I suggest that the site form a debate about what the basis of Law is (one that transcends the nation-state because it appeals to universal principles, for example) or ...
Sure, you can ask a question about what the basis of Law is. Questions about [l]egal terms and language, doctrines and theory are specifically on topic.
However, this isn't a license to canvas unreferenced, unverifiable opinion. Answers to such a question should still be independently verifiable, or supported by the literature. Neither is it an opportunity for self-publishing.
... or make an attempt to state what principles of Law form the basis for discussion and in answering questions.
Generally, this is informed by jurisdiction. However, due to the apparent demographics of the site, the principles are skewed heavily in favour of common law systems; specifically that of the United States, although a fair number of other countries have been asked about.
If the question is about a common law jurisdiction, use common law principles. If it's about a civil law jurisdiction, use civil law principles. And so on.
Without this, there is useless and possibly or actually harmful banter.
Again, I assume you mean answers. If you see something that is possibly or actually harmful, you can either write a better answer, or comment to indicate how the answer could be improved. If the answer is likely unsalvageable, then once you have enough reputation you can vote to delete these answers. However, suggesting improvements is strongly encouraged.
Is Law SE primarily for arguing what the present, written Law says or what a perfect Judge would decide--if such could exist?
I've left this until last because I thought I'd be able to summarise my answer. In any case this title presents a false dichotomy. For the majority common law systems, we focus on the law - case law and statute - as it is, and we presume that a judge will act in accordance with established legal doctrine and principles.
There's a couple of reasons for this:
- As mentioned above, judges generally do not have unfettered and absolute discretion. While this differs in other legal systems, there are other principles to which judges in civil law jurisdictions should adhere; and
- There's absolutely no point in supposing that a judge will make completely arbitrary decisions. If the outcome of every case that was ever, and that will ever be heard was based on nothing more or less than the judge's personal interpretation of legal principles, we might as well shut the site down right now.
In that case, perhaps you should call this SE cite "case builder" rather than Law SE which makes it sound quasi-authoritative. (comment)
This would be unusual. The Stack Exchange 2.0 (that is, sites after Stack overflow, Super User and Server Fault) network of sites are named for their subject matter, and occasionally their audience, not for the end product.
- Writers (not "books, poetry, and other writing")
- Physics (not "time travel")
- Chemistry (not "chemical compounds")
- English Language Learners (not "fluent English speakers")
- Drupal (not "CMS")
- Cooking (not "dinner")
- Code Review (not "working code")
I don't think I need more examples.
We want to create a source of knowledge that is as accurate as possible. However, Law SE doesn't make claims to any kind of authority. This is as silly as saying that /r/law should be called "chatting about the law" because it sounds quasi-authoritative. We've put a notice on just about every page we can so that users don't assume this.
Educational? Yes. Authoritative? No.