LEARNED TREATISES AS AN EXCEPTION TO THE HEARSAY RULE (PHILIPPINE SETTING)

I. OVERVIEW

Under Philippine remedial law (specifically under the Rules of Court on Evidence), the general rule is that hearsay evidence is inadmissible because its source cannot be subjected to cross-examination. However, there are several exceptions to this rule. One such exception is the Learned Treatise exception, which allows certain authoritative writings to be admitted in evidence for the truth of the matters stated therein—even if the author is not available to testify—provided specific foundational requirements are met.

Historically, the learned treatise exception recognizes that certain written works enjoy high reliability because they are produced by scholars or experts in a field, reflect a consensus of the relevant scientific, technical, or specialized community, and are subject to professional scrutiny. Thus, despite being hearsay, these works may be considered sufficiently trustworthy to be admitted in judicial proceedings.

II. LEGAL BASIS

A. Relevant Rule in the 2019 Amendments to the Rules on Evidence

Under the 2019 Amendments to the Rules of Court, found in Rule 130 (Rules on Evidence), “Learned Treatises” are expressly recognized as an exception to the hearsay rule. The pertinent section (often listed as Section 48 of Rule 130 in the revised numbering) states in substance:

Section [48]. Learned treatises. – A statement contained in a published treatise, periodical, or pamphlet on a subject of law, history, science, or art is admissible as tending to prove the truth of the matter stated if:
(a) the court takes judicial notice, or
(b) an expert testifies,
that the writer of the statement is recognized in his or her profession or calling as expert in the subject.
If admitted, the statement may be read into evidence but not received as exhibit.

Although the numbering can vary (depending on the publisher or version of the 2019 Rules), this text captures the essence of the learned treatise exception under Philippine rules.

III. RATIONALE AND POLICY CONSIDERATIONS

Reliability – Learned treatises (textbooks, periodicals, treatises) in specialized fields are generally considered to possess an inherent reliability due to peer review, reputation of the author, and methodology employed in such works.
Necessity – In many instances, these texts are critical in explaining and understanding complex or technical subjects (e.g., medical diagnoses, engineering principles, specialized legal questions), especially when an expert testifies.
Expert Endorsement – By requiring that a treatise’s authority be established through testimony of an expert or by judicial notice, the rule ensures only reliable authorities are admitted.

IV. ELEMENTS AND REQUIREMENTS FOR ADMISSIBILITY

To invoke this exception successfully, the proponent must show:

Nature of the Publication
- It must be a published treatise, periodical, or pamphlet.
- The subject matter covered by the publication must be one of law, history, science, or art, or some similarly recognized specialized field.
Recognition of the Author’s Expertise
- The publication (or its author) must be established as a reliable authority in the field.
- How to Establish Authority:
  - Expert witness testimony on direct or cross: The expert can attest that the treatise is recognized and authoritative.
  - Judicial notice: In some cases, the court may, on its own, recognize that a certain treatise is authoritative and well-established.
  - Admission by an adverse expert or “other expert testimony.”
Connection to Expert Testimony or Judicial Notice
- Typically, a live expert witness must either use or acknowledge the treatise. This might happen:
  - On direct examination: The proponent’s expert relies on the text as support for his or her opinion.
  - On cross-examination: The adverse counsel calls the treatise to the attention of the expert to test or impeach the expert’s conclusion.
Limitation on Form of Admission
- The treatise itself is not received as an exhibit; rather, the relevant portions are read into the record.
- This rule exists to prevent the jury (in jury systems) or the court (in bench trials) from being misled by entire volumes of extraneous material, much of which may not be relevant. In Philippine practice—where judges are professional triers of fact—the approach similarly ensures that only the portions with probative value are placed on the record, while avoiding undue consumption of time or risk of confusion.

V. PROCEDURE FOR USING A LEARNED TREATISE DURING TRIAL

Laying the Foundation
- Before reading from or referring to the treatise in open court, the examining lawyer must lay the groundwork:
  a. Ask the expert witness if he or she recognizes the treatise, periodical, or pamphlet.
  b. The expert should testify that the publication is indeed authoritative and widely recognized in the field. Alternatively, the proponent might move that judicial notice be taken of its authoritative status (rare, except for extremely famous works).
Offer of the Excerpt for Reading into the Record
- After establishing the treatise’s authority, the relevant portion of the text may be read into evidence.
- The entire publication is not marked as an exhibit; only the pertinent parts are actually “offered” into evidence by being read into the transcript or summarized by the witness.
Cross-Examination
- Once an expert acknowledges a treatise as authoritative, the adverse counsel may then use it freely to cross-examine or impeach that expert by citing contradictory statements found in the same or other recognized treatises.
Court’s Discretion
- The trial court has wide discretion in determining the reliability and relevance of any purported learned treatise. It may exclude references that are cumulative, misleading, or insufficiently authenticated as authoritative.

VI. SCOPE OF USE

Substantive Evidence
- Statements from a learned treatise, once admitted, may be used for the truth of the matter asserted—i.e., as substantive evidence, not merely for impeachment. This is the essence of the hearsay exception.
Impeachment of Expert Witness
- Learned treatises may also be used to impeach an expert’s credibility if the expert takes a position that is directly contradicted by an authority the expert concedes to be authoritative.
Bolstering Expert Testimony
- Conversely, a party may bolster its own expert by showing that the expert’s opinions align with well-regarded references.

VII. LIMITATIONS AND PITFALLS

Lack of Proper Foundation
- If the proponent fails to establish that the treatise or its author is “recognized” in the profession or calling, the treatise remains hearsay and is inadmissible.
Relevance
- Even if a treatise is authoritative, it must still be relevant to the issues in the case. Irrelevant portions may be excluded.
No Physical Admission as Exhibit
- The text of the rule clearly states that while the statements may be read, the treatise is not received as a physical exhibit. Lawyers sometimes overlook this and attempt to mark the entire publication as an exhibit, which can be disallowed.
Partial Reliance or “Cherry-Picking”
- Parties must be mindful not to quote only favorable excerpts while ignoring contradictory sections in the same text. The opposing party may point out contradictory statements, creating confusion or undermining credibility.
Misleading the Court
- A treatise that has become outdated or has been discredited by more recent research may be challenged as no longer authoritative. The authenticity and currency of the text must be established.

VIII. ILLUSTRATIVE JURISPRUDENCE

While Philippine Supreme Court decisions directly focusing on the “learned treatise” exception are not as plentiful as decisions on other hearsay exceptions, the principle is often cited in tandem with expert testimony rules. Courts have recognized that expert testimony can be tested for accuracy or reliability by reference to authoritative texts. Key points from case law include:

The necessity of an expert – The Supreme Court emphasizes that if an expert is not presented to validate the treatise or if judicial notice is not feasible, the treatise will not qualify as an exception.
Requirement of clarity and reliability – Courts will reject attempts to rely on lesser-known or obscure references that cannot readily be proven authoritative.
Support or contradiction of expert’s opinion – Using treatises effectively can either bolster one’s expert or discredit the opposing expert; however, the text must be consistent with recognized scientific, medical, or technical knowledge.

(If researching specific Supreme Court rulings, look for cases on expert testimony in medical malpractice or engineering defect litigation, where references to medical or technical treatises often surface as corroborative proof.)

IX. STRATEGIC IMPORTANCE FOR LAWYERS

Preparation – Identify in advance any treatises, textbooks, or articles your expert is likely to rely upon, and be ready to establish their authority on direct examination.
Cross-Examination Tool – You can effectively undermine an adverse expert by highlighting contradictory statements in treatises he/she acknowledges as authoritative.
Do Not Overuse – Judges may become wary if you inundate the record with multiple treatises. Clarity, precision, and direct relevance to the issues at hand are crucial.
Stay Updated – In fields where knowledge evolves rapidly (e.g., medicine, technology), outdated or superseded references risk being impeached as unreliable.

X. SUMMARY OF KEY POINTS

Exception to Hearsay: Learned treatises are specifically enumerated as an exception to the hearsay rule under the Philippine Rules on Evidence.
Foundation: Must be a published, authoritative work in law, history, science, or art, recognized by an expert or judicial notice.
Form of Admission: Excerpts are read into evidence but not physically received as an exhibit.
Uses: Such excerpts can be used to prove the truth of technical or specialized information, to impeach or bolster expert testimony, and to assist the court in understanding complex matters.
Limitations: Requires a proper showing of authoritativeness, relevance, and current validity. Courts have discretion to exclude or limit if these are not convincingly established.

CONCLUSION

The Learned Treatise exception under Philippine law underscores the court’s recognition that not all hearsay is inherently unreliable. Where a written work’s authoritativeness is proved and the treatise is relevant to the expert issues at bar, its content may be admitted for the truth of the matter.

For lawyers, the strategic deployment of learned treatises can decisively shape a case involving technical or specialized questions—either strengthening an expert’s position or discrediting an opponent’s. Meticulous preparation, proper foundation, and a clear demonstration of authority and relevance remain the pillars for effectively invoking this important hearsay exception.