When the Philippine Senate convenes as an impeachment court, it assumes one of the Constitution’s most demanding duties. Impeachment is not ordinary legislation. Under the 1987 Constitution, the House of Representatives has the exclusive power to initiate impeachment cases, while the Senate has the sole power to try and decide them. Senators must take an oath or affirmation for that purpose, and conviction requires the concurrence of two-thirds of all members of the Senate. The process therefore asks senators to step beyond political advocacy and act as constitutional adjudicators. Its legitimacy rests not only on compliance with legal procedure, but also on the quality of judgment exercised by those entrusted to decide.

Rolf Dobelli’s The Art of Thinking Clearly (2013) offers two concepts that are particularly useful in examining the challenges faced by any impeachment court: domain dependence and the false-consensus effect. These are not simply psychological curiosities. If left unchecked, they can influence how evidence is assessed and how constitutional obligations are discharged, ultimately affecting both the credibility of the verdict and the institution itself.

Bias One: Domain Dependence

Domain dependence refers to the tendency of expertise in one field to transfer poorly to another. Knowledge is often highly specialized. Excellence in business, entertainment, politics, or even academic economics does not automatically prepare a person to evaluate evidence, weigh testimony, or distinguish between competing legal arguments.

Dobelli illustrates this point through Nobel laureate Harry Markowitz, whose pioneering work on portfolio theory transformed modern finance. Yet when arranging his own investment portfolio, Markowitz reportedly chose a simple 50-50 split between equities and bonds rather than applying the sophisticated optimization methods that helped earn him the Nobel Prize in 1990. Expertise, in other words, has limits.

The lesson is not that only lawyers are fit to sit in judgment. The Constitution deliberately does not require senators to hold law degrees before serving as judges in impeachment proceedings. Legal training, by itself, also does not guarantee sound judgment. Questions such as whether a public official abused public trust, whether testimony is credible, or whether evidence is persuasive ultimately require integrity, common sense, intellectual discipline, and a willingness to understand the record before reaching conclusions.

Still, impeachment imposes responsibilities that go beyond the usual work of legislation. Senators are expected to appreciate evidence, understand legal standards, and separate advocacy from adjudication. If they fail to recognize the limits of their own expertise, or if they substitute instinct for careful examination of the facts, domain dependence becomes more than an individual weakness. It becomes an institutional risk.

Bias Two: The False-Consensus Effect

The second bias is even more consequential. The false-consensus effect is the tendency of individuals to believe that their own views are widely shared, objectively correct, and therefore entitled to prevail. It is common in tightly knit political, ideological, or interest groups, where mutually reinforcing opinions gradually displace independent judgment.

An impeachment court cannot function properly if this bias takes hold. Senators are constitutionally expected to put aside partisan loyalties and political calculations in favor of an impartial evaluation of the evidence placed before them. While senators inevitably bring political backgrounds into the chamber, the constitutional role of an impeachment judge requires a different mindset. The question is no longer which political position is advantageous, but whether the evidence satisfies the constitutional standards for accountability.

In ordinary courts, judges whose impartiality may reasonably be questioned can voluntarily inhibit themselves or be challenged for bias, because justice must not only be done but must also be seen to be done. Impeachment operates under different constitutional and Senate rules, but the underlying principle remains relevant: public confidence depends on visible fairness and intellectual independence.

When domain dependence and the false-consensus effect reinforce each other, the consequences become especially troubling. One weakens competence; the other weakens objectivity. Together, they can create an environment in which evidence is misunderstood, dismissed prematurely, or interpreted primarily through political allegiance rather than constitutional duty.

Why Biases Matter in Impeachment

Recent impeachment proceedings have shown why these concerns matter.

One example involves the treatment of publicly available video statements that had already been acknowledged by the respondent’s own legal team. These recordings were not obscure pieces of evidence. They had been seen by millions of Filipinos through televised press conferences and social media platforms. Raising speculative doubts about their authenticity, despite the surrounding circumstances and prior admissions, shows how cognitive biases can complicate what should otherwise be a straightforward assessment of evidence.

More fundamentally, the significance of these recordings lies not merely in the words spoken, but in what they may establish under the constitutional standard that applies to impeachment. As officials of the National Bureau of Investigation argued, the issue goes beyond whether particular statements amount to criminal conduct. The relevant constitutional inquiry is whether the conduct demonstrates betrayal of public trust or raises serious questions about fitness to continue occupying public office.

That distinction is crucial. Impeachment is not primarily designed to impose criminal penalties. Its purpose is to uphold institutional accountability. It asks whether a public official has preserved the integrity, prudence, and public confidence required by constitutional office. The evidentiary threshold therefore differs from that of an ordinary criminal prosecution.

Accordingly, the duty of senator-judges is not to replicate the work of criminal courts. It is to examine carefully every document, testimony, and argument presented before them, applying the constitutional standard rather than political preference. Because impeachment can remove an official from office and may also carry disqualification from holding future public office, the process requires both procedural restraint and seriousness of judgment.

The credibility of the process depends on disciplined evaluation of evidence, not preconceived narratives. This is why arguments aimed mainly at reducing the seriousness of the evidence, attacking witnesses without addressing the substance of their testimony, or recasting constitutional questions as ordinary political disagreements or neighbor disputes require careful scrutiny. Such approaches may be entirely legitimate in adversarial advocacy. They become problematic, however, if they replace the independent judgment expected from those acting as constitutional adjudicators.

Beyond the Philosopher King

The challenge is therefore larger than any individual senator or any single respondent. It concerns the institutional culture surrounding constitutional accountability.

This brings the discussion beyond Plato’s ideal of the philosopher king. Modern constitutional democracies do not expect perfect rulers endowed with extraordinary wisdom. Aristotle offered a more practical vision: citizens collectively share responsibility for governance through institutions, laws, and civic participation.

Yet constitutional government still demands minimum standards from those entrusted with public authority. The Ming Dynasty philosopher Wang Yangming expressed this expectation through his idea of the “unity of knowledge and action,” which holds that public responsibility requires both understanding and the ability to act consistently with that understanding. Knowledge without integrity is inadequate. Integrity without informed judgment is also insufficient.

Niall Ferguson makes a similar point in his foreword to Henry Kissinger’s final book, Genesis: Artificial Intelligence, Hope, and the Human Spirit (2024 with Craig Mundie and Eric Schmidt). Modern societies possess unprecedented technological capabilities, yet wisdom remains scarce. Distinguishing what advances the public good from what merely reflects passing passions requires discernment as much as intelligence.

That insight applies equally to constitutional institutions. Democracies succeed not because their officials possess extraordinary brilliance, but because they consistently exercise disciplined judgment, intellectual humility, and respect for institutional boundaries.

Alexis de Tocqueville understood this long ago. Democracy, he argued, depends less on constitutional texts than on the civic virtues and habits of those who administer them. Institutions remain strong only when public officials respect constitutional limits and citizens insist that those limits apply equally to everyone.

Impeachment therefore goes well beyond political competition. It is one of the Constitution’s principal mechanisms for preserving public accountability. Each proceeding becomes a test not only of the conduct of one public official, but also of the capacity of constitutional institutions to function impartially.

Public trust is built slowly but can be lost with remarkable speed. If citizens conclude that constitutional processes are shaped more by cognitive bias, political loyalty, or predetermined outcomes than by careful evaluation of evidence, confidence in democratic institutions inevitably erodes.

That is why domain dependence and the false-consensus effect deserve serious attention. They are not abstract psychological concepts. They are institutional vulnerabilities capable of shaping constitutional outcomes. An impeachment court that recognizes and guards against these biases strengthens both the legitimacy of its verdict and the credibility of the constitutional order. One that allows them to dominate risks weakening not only a single proceeding, but also public confidence in the rule of law itself.

Diwa C. Guinigundo is the former deputy governor for the Monetary and Economics Sector of the Bangko Sentral ng Pilipinas (BSP). He served the BSP for 41 years. From 2001 to 2003, he was alternate executive director at the International Monetary Fund in Washington, DC. He is the senior pastor of the Fullness of Christ International Ministries in Mandaluyong.