I am essentially asking for a quote that I know exists but cannot remember.
A Law Lord from the British House of Lords either made a remark or an actual ruling on the subject of whether a ruling from a final court could be appealed. It was something like "otherwise, nothing would ever be settled and there would be no finality".
I'm sure I read it in some kind of "intro to law" book.
One direct statement about this is in White v. Tommey [1853] 10 E.R. 483, in which the House of Lords had to consider whether to allow a rehearing of a case which they had previously decided, on the basis that there had been misrepresentation the first time round which affected their judgement. The Lord Chancellor, Lord Cranworth, said:
What ought your Lordships to do in this state of things? It was pressed very strongly on the part of Tommey by his counsel, that your Lordships in truth have no jurisdiction; that after a matter has once been heard and adjudicated upon in this ultimate Court of appeal, there is an end of it, that there must be an end somewhere, and that if it can be said that the trustees can be heard now to come and call in question the decree of 1850, what is to prevent Mr. Tommey coming afterwards, in 1860, and praying your Lordships to reconsider it again, and so toties quoties to the very end of time?
In this case, the Lords sent the case back to the Court of Chancery in Ireland, setting aside their earlier orders relating to the appeal. This did not amount to a rehearing of the merits in the House of Lords, but their correction of a mistake in the proceedings and restoring the status quo ante.
In an earlier case, Stewart v. Agnew [1823] 1 Shaw 413, another Lord Chancellor, Lord Eldon, observed:
It is infinitely better that the matter should be here finally decided upon one hearing, even if the decision is wrong, than that there should be a new litigation unknown to our proceedings, as to this matter of rehearing; - nor can any one say where it is to stop. In general, it is to be hoped that the decisions of this House are right; but, whether right or wrong, it has been taken for granted that considerations of infinitely greater moment than the considerations which arise out of the particular mischief in particular cases, have led this House to determine, that where a matter has been heard between parties at the Bar, and the House has given its decision upon the merits discussed by those parties, the House will not rehear the cause.
On direct appeal, the issue is that there is no court higher to appeal to, and there is a deadline for filing motions to reconsider in the procedural rules.
In terms of reopening the matter in other proceedings, there are two main finality doctrines in civil cases, res judiciata which prevents cases from being revisited, and collateral estoppel which prevents issues that were tried within cases from being revisited.
I found the quote I was thinking of. It was Lord Halsbury in London Tramways v London City Council 1898
My Lords, it is totally impossible, as it appears to me, to disregard the whole current of authority upon this subject, and to suppose that what some people call an "extraordinary case," an "unusual case," a case somewhat different from the common, in the opinion of each litigant in turn, is sufficient to justify the rehearing and rearguing before the final Court of Appeal of a question which has been already decided. Of course I do not deny that cases of individual hardship may arise, and there may be a current of opinion in the profession that such and such a judgment was erroneous; but what is that occasional interference with what is perhaps abstract justice as compared with the inconvenience - the disastrous inconvenience - of having each question subject to being reargued and the dealings of mankind rendered doubtful by reason of different decisions, so that in truth and in fact there would be no real final Court of Appeal? My Lords, "interest rei publicæ" that there should be "finis litium" at some time, and there could be no "finis litium" if it were possible to suggest in each case that it might be reargued, because it is "not an ordinary case," whatever that may mean. Under these circumstances I am of opinion that we ought not to allow this question to be reargued.