What is the origin and basis of stare decisis?

Question

When, where, how, and why did the doctrine that courts must have regard to the entirety of the infinitely ever growing corpus of judicial decisions that came before that sub judice and align their ruling to those that are comparable?

And why are prior judges’ powers of interpretations automatically seen to be more capable and robust than, so as to bind and prevail over, subsequent judges’ interpretative abilities?

Answer 1

I assume you are asking about horizontal stare decisis: a court following its own previous holdings or those of courts of coordinate jurisdiction (e.g. courts at the same "level" in the judiciary). I say this because your incredulity does not seem to extend to the notion that appellate courts can bind lower courts.

You ask:

why are prior judges’ powers of interpretations automatically seen to be more capable and robust than, so as to bind and prevail over, subsequent judges’ interpretative abilities?

This is not the rationale for horizontal stare decisis. The doctrine is not at all based on the premise that the first court or judge to answer got it correct. Justification was given in a concurring opinion in R. v. Kirkpatrick, 2022 SCC 33:

Stare decisis promotes: (1) legal certainty and stability, allowing people to plan and manage their affairs; (2) the rule of law, such that people are subject to similar rules; and (3) the legitimate and efficient exercise of judicial authority (citations omitted).

And horizontal stare decisis is not absolute. Common-law jurisdictions have developed limited avenues for departure. For example, in Canada, a lower court can depart from previous decisions of courts of coordinate jurisdiction when (R. v. Sullivan, 2022 SCC 19):

1. The rationale of an earlier decision has been undermined by subsequent appellate decisions;
2. The earlier decision was reached per incuriam (“through carelessness” or “by inadvertence”); or
3. The earlier decision was not fully considered, e.g. taken in exigent circumstances.

Even apex courts have developed a sense of internal obligation to follow their own precedents. But departure from previous decisions may be justified where (see the Kirkpatrick concurrence at para. 202):

1. The Court rendering the decision failed to have regard to a binding authority or relevant statute (“per incuriam”);

2. The decision has proven unworkable (“unworkability”); or

3. The decision’s rationale has been eroded by significant societal or legal change (“foundational erosion”).

This has been viewed to "strike the appropriate balance between the competing demands of certainty, correctness and the even-handed development of the law" (R. v. Sullivan, 2022 SCC 19). "Adherence to precedent furthers basic rule of law values such as consistency, certainty, fairness, predictability, and sound judicial administration."

Answer 2

The underlying idea has been implicit in law for over a millenium in England. The term dates back at least to Sir Matthew Hale who cites his doctrine of stare decisis in Hanslap v. Cater (1673). Blackstone in Commentaries of the laws of England Book 1 section 3 explains that the laws "receive their binding power, and the force of laws, by long and immemorial usage, and by their universal reception throughout the kingdom" – this is what stare decisis is "about". In the same era as Hale, Coke in Institutes of the Lawes of England explains that "our book cases are the best proofs what the Law is" and are cited as authority for what the law is.

This may seem a bit strange in an era where "the law" is meticulously documented and instantly available on your phone, but the whole point of developing "the common law" since Henry II was to create a single legal system supplanting myriad local systems (Mercian, West Saxon and Danish Law), the content of which were not clearly established. As Blackstone explains,

But here a very natural, and very material, question arises: how are these customs or maxims to be known, and by whom is their validity to be determined? The answer is, by the judges in the several courts of justice. They are the depositary of the laws; the living oracles, who must decide in all cases of doubt, and who are bound by an oath to decide according to the law of the land. Their knowlege of that law is derived from experience and study

...

these judicial decisions are the principal and most authoritative evidence, that can be given, of the existence of such a custom as shall form a part of the common law.

Blackstone states that

it is an established rule to abide by former precedents, where the same points come again in litigation; as well to keep the scale of justice even and steady, and not liable to waver with every new judge's opinion; as also because the law in that case being solemnly declared and determined, what before was uncertain, and perhaps indifferent, is now become a permanent rule, which it is not in the breast of any subsequent judge to alter or vary from, according to his private sentiments: he being sworn to determine, not according to his own private judgment, but according to the known laws and customs of the land; not delegated to pronounce a new law, but to maintain and expound the old one.

It is assumed that judges competently perceive what the law is, and that the law is a non-contradictory whole. It would therefore be a contradiction to flout a prior decision, unless of course the earlier decision was clearly in error. Yet, Blackstone notes that

this rule admits of exception, where the former determination is most evidently contrary to reason; much more if it be contrary to the divine law. But even in such cases the subsequent judges do not pretend to make a new law, but to vindicate the old one from misrepresentation. For if it be found that the former decision is manifestly absurd or unjust, it is declared, not that such a sentence was bad law, but that it was not law; that is, that it is not the established custom of the realm, as has been erroneously determined.

For an extended treatment of precedent and stare decisis, see Duxbury (2008) The nature and authority of precedent.