What is the Blackstone's ratio in criminal law?

In criminal law, Blackstone's ratio (also known as the Blackstone ratio or Blackstone's formulation) is the idea that: "It is better that ten guilty persons escape than that one innocent suffer." (Sir William Blackstone, COMMENTARIES ON THE LAWS OF ENGLAND, 9th ed., book 4, chapter 27, p. 358, 1783. reprinted 1978)

It has been eight (8) years since Dy and Cepeda have been in confinement. Surely, this acquittal will be welcomed by the accused. However, there remains no recompense for the time spent in prison under an erroneous conviction, regardless of its duration. It is in this light that the Court restores the liberty of the accused. (G.R. No. 229833, July 29, 2019)

It is a fundamental principle of criminal law that conviction of the accused must be beyond reasonable doubt. Judges have to adhere to this doctrine faithfully to avoid the possibility of convicting an innocent person. For his peace of mind, the judge would prefer to absolve the accused whose guilt is tainted by an iota of doubt in his mind because the prosecution failed to establish guilt beyond reasonable doubt due to the weakness or insufficiency of evidence. In other words, for conviction, the guilt of the accused must be established with 100% certainty. As the saying goes: it were better that a thousand guilty criminals go scot free rather than that one innocent person goes to jail. (J. Elihu A. Ybañez [2015]. "The Dispensation of Justice Constraints and Solutions. Court of Appeals Journal. https://ca.judiciary.gov.ph.)

Basic is the doctrine that proof beyond reasonable doubt is needed to overcome presumption of innocence. The guilt of the accused must be proved beyond reasonable doubt, otherwise, the Court is left without any other recourse but to rule acquittal. Courts should be guided by the principle that it would be better to set free ten men who might be probably guilty of the crime charged than to convict one innocent man for a crime he did not commit. In this instance, while there are accusing fingers pointing to petitioner as the perpetrator of the crime, the circumstances obtaining in this case leave some probability that she is innocent. (Buenaventura v. People, G.R. No. 148079, June 27, 2006, citing People vs. Reyes, G.R. Nos. L-36874-76, September 30, 1974 and People vs. Maliwanag, G.R. No. L-30302, August 14, 1974)

We are enraged by the shocking death suffered by the victim and we commiserate with her family. But with seeds of doubt planted in our minds by unexplained circumstances in this case, we are unable to accept the lower court's conclusion to convict appellants. We cannot in conscience accept the prosecution's evidence here as sufficient proof required to convict appellants of murder. Hence, here we must reckon with a dictum of the law, in dubilis reus est absolvendus. All doubts must be resolved in favor of the accused. Nowhere is this rule more compelling than in a case involving the death penalty for a truly humanitarian Court would rather set ten guilty men free than send one innocent man to the death row. Perforce, we must declare both appellants not guilty and set them free. (G.R. NO. 150129 April 6, 2005)

All told, the guilt of the accused-appellant was not proven beyond reasonable doubt measured by the required moral certainty of conviction. The evidence presented by the prosecution was not enough to overcome the presumption of innocence as constitutionally ordained. Indeed, it would be better to set free ten men who might be probably guilty of the crime charged than to convict one innocent man for a crime he did not commit. Moreover, as Justice Holmes declared: I think it is a less evil that some criminals should escape than that the government should play an ignoble part. (G.R. No. 132165. March 26, 2003)