Obedience to the rule of law is the bedrock of the Philippine justice system.^[251] In order to expound and define the true meaning and operation of these laws, they must first be ascertained by judicial determination, and in order "to produce uniformity in these determinations, they ought to be submitted, in the last resort, to one supreme tribunal xxx authorized to settle and declare in the last resort a uniform rule of civil justice."^[252]

The rules of evidence, authorized by the Constitution, is a means by which uniformity is instituted in the judicial system whether in courts of law or administrative agencies granted quasi-adjudicatory power. These rules govern the means of ascertaining the truth respecting a matter of fact.^[253]

It must be emphasized that ascertaining evidence does not entail absolute certainty. Under Rule 128 of the Rules of Court, evidence must only induce belief in the existence of a fact in issue, thus:

Section 4. Relevancy; collateral matters. - Evidence must have such a relation to the fact in issue as to induce belief in its existence or nonexistence. Evidence on collateral matters shall not be allowed, except when it tends in any reasonable degree to establish the probability or improbability of the fact in issue. (Emphasis supplied)

Hence, judges are not precluded from drawing conclusions from inferences based on established facts. In the case of Joaquin v. Navarro,^[254] the Court proceeded to discuss this process:^[255]

In speaking of inference the rule can not mean beyond doubt, for "inference is never certainty, but it may be plain enough to justify a finding of fact."

In Montemayor v. Bundalian,^[21] this Court laid down the guidelines for the judicial review of decisions rendered by administrative agencies in the exercise of their quasi-judicial powers, as follows:

First, the burden is on the complainant to prove by substantial evidence the allegations in his complaint. Substantial evidence is more than a mere scintilla of evidence.  It means such relevant evidence as a reasonable mind might accept as adequate to support a conclusion, even if other minds equally reasonable might conceivably opine otherwise.  Second, in reviewing administrative decisions of the executive branch of the government, the findings of facts made therein are to be respected so long as they are supported by substantial evidence.  Hence, it is not for the reviewing court to weigh the conflicting evidence, determine the credibility of witnesses, or otherwise substitute its judgment for that of the administrative agency with respect to the sufficiency of evidence.

Third, administrative decisions in matters within the executive jurisdiction can only be set aside on proof of gross abuse of discretion, fraud, or error of law.  These principles negate the power of the reviewing court to re-examine the sufficiency of the evidence in an administrative case as if originally instituted therein, and do not authorize the court to receive additional evidence that was not submitted to the administrative agency concerned.  [emphases ours]

 Absent any clear and convincingproof to the contrary, a notarized document enjoys the presumption of regularity and is conclusive as to the truthfulness of its contents. ^[42]

Settled is the rule in our jurisdiction that a notarized document has in its favor the presumption of regularity, and to overcome the same, there must be evidence that is clear, convincing and more than merely preponderant; otherwise the document should be upheld. Clearly, the positive presumption of the due execution of the subject real estate mortgage outweighs [petitioners'] bare and unsubstantiated denial that the parcels of land covered by TCT Nos. T-225132 and T-225131 were among those intended to secure the loan of One Million Pesos.  Their imputation of fraud among the officials of [the bank] is weak and unpersuasive. x x x

The burden of proof shifts to the person invoking self-defense, who, with clear andconvincing evidence, must establish all the following requisites: (1) unlawful aggression on the part of the victim, (2) reasonable necessity of the means employed to prevent or repel it, and (3) lack of sufficient provocation on the part of the person claiming self-defense. Upon failure to establish these requisites, conviction is inevitable because the accused, by setting up self-defense, admits being the author of the killing.

As early as 1924, some ABA members have questioned the form and function of the canons. Among their concerns was the "revolving door" or "the process by which lawyers and others temporarily enter government service from private life and then leave it for large fees in private practice, where they can exploit information, contacts, and influence garnered in government service."^[25] These concerns were classified as adverse-interest conflicts' and "congruent-interest conflicts." "Adverse-interest conflicts" exist where the matter in which the former government lawyer represents a client in private practice is substantially related to a matter that the lawyer dealt with while employed by the government and the interests of the current and former are adverse.^[26] On the other hand, "congruent-interest representation conflicts" are unique to government lawyers and apply primarily to former government lawyers.^[27] For several years, the ABA attempted to correct and update the canons through new canons, individual amendments and interpretative opinions. In 1928, the ABA amended one canon and added thirteen new canons.^[28] To deal with problems peculiar to former government lawyers, Canon 36 was minted which disqualified them both for "adverse-interest conflicts" and "congruent-interest representation conflicts."^[29] The rationale for disqualification is rooted in a concern that the government lawyer's largely discretionary actions would be influenced by the temptation to take action on behalf of the government client that later could be to the advantage of parties who might later become private practice clients

Moreover, this "inconsistency" refers only to a collateral matter and does not deviate from the fact that accused-appellant was positively and categorically identified as the perpetrator of the crime.  The "inconsistency" only bolsters the credibility of Lejano as it shows that his testimony was not rehearsed nor perjured.  Thus -

Inconsistencies in the testimonies of the prosecution witnesses with respect to minor details and collateral matters do not affect the substance of their declarations nor the veracity or weight of their testimony.  In fact, these minor inconsistencies enhance the credibility of the witnesses for they remove any suspicion that their testimonies were contrived or rehearsed.  In People v. Maglente [306 SCRA 546 (1999)], this Court ruled that inconsistencies in details which are irrelevant to the elements of the crime are not grounds for acquittal.^[5]

The defense maintains that Lejano is a perjured witness as he could not even state the exact date when his cousin died.  Again, this Court is not convinced.  Whatever seeming discrepancy there was in Lejano's testimony was not as irreconcilable nor material or relevant as to merit its complete disregard by the court.  The date when the victim died refers only to a collateral matter.  The established fact remains that accused-appellant stabbed the victim to death.