Authentication & Best Evidence (Rules 901-1008)
Evidence · Lesson 06
Authentication & Best Evidence (Rules 901-1008)
這一課問的是：證物是否經適當鑑證？最佳證據規則是否要求原本？
ActorActObjectStandardConsequence
Visual Scene · the picture in your head
Issue. Has the item been properly authenticated, and does the best evidence rule require the original?
這一課問的是：證物是否經適當鑑證？最佳證據規則是否要求原本？
Core Terminology · 7 must-know
Tap a card to flip and reveal the meaning.
Rule 901
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Authentication requires evidence sufficient to support finding item is what proponent claims.
Rule 901。
self-authenticating
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Rule 902 items requiring no extrinsic evidence.
自證。
Best Evidence Rule
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Rule 1002: original required to prove content of writing, recording, photograph.
最佳證據規則。
duplicate
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Rule 1003: admissible to same extent as original unless genuine question.
複本。
Rule 1004
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Original not required if lost, destroyed, etc.
1004 例外。
chain of custody
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Reasonable showing of unbroken handling.
保管鏈。
voice identification
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Witness familiar with voice may identify.
聲音辨識。
Issue · what this lesson is really about
Has the item been properly authenticated, and does the best evidence rule require the original?
這一課問的是：證物是否經適當鑑證？最佳證據規則是否要求原本？
Trigger words & phrases that should flag this issue:
authenticateoriginalduplicatechain of custodywritingphoto
Expression Bank · how lawyers actually say it
Six function → sentence patterns. Use these in essay applications.
| Function | English sentence | 中文 |
|---|---|---|
| State authentication | Authentication requires evidence sufficient for finder of fact to find item is what proponent claims. | 鑑證要求充分證據使事實認定人認定真實。 |
| Apply self-authentication | Public records, certified copies, newspapers, and trade inscriptions are self-authenticating. | 公共記錄、認證副本、報紙、商標自證。 |
| Apply BER | Best Evidence Rule applies only to proving content of writing, recording, or photograph. | BER 僅及證明書面、錄音、照片之「內容」。 |
| Apply 1003 | Duplicates are admissible unless genuine question of authenticity or unfair. | 複本可採除非有真實性疑慮或不公。 |
Rule Sentence · the workhorse
Authentication under Rule 901 requires evidence sufficient to support a finding that the item is what the proponent claims; the best evidence rule under Rule 1002 requires the original to prove the content of a writing, recording, or photograph, with duplicates and other secondary evidence admissible under Rules 1003-1004.
Sentence Anatomy · 5 roles, 5 colors
Every rule sentence breaks into five visual roles.
Actor 行為人proponent提出人
Act 行為authenticating + offering鑑證 + 提出
Object 對象item / writing / recording物 / 書面 / 錄音
Standard 法律標準Rule 901 + Rule 1002Rule 901 + 1002
Consequence 後果admitted or excluded採用或排除
Casebook Snapshot · a real American case
United States v. Yamashita
Holding. Digital evidence is authenticated under Rule 901 when the proponent presents evidence sufficient for a reasonable jury to find the item is what the proponent claims — including metadata, witness testimony to creation/maintenance, and distinctive characteristics. The bar is not high.
Why it matters. Rule 901's threshold is functional: enough evidence to support a finding, not certainty.
Rule 901 鑑證為功能性：足以支持認定即可，無需確定。
Common Mistakes · what trips students
✗ BER 適用所有書面證據。
✓ Only when content of writing is what's being proved.
僅當「內容」即所證者。
✗ chain of custody 必須完美。
✓ Reasonable showing suffices.
合理證明即足。
Mini IRAC · build the Application
Issue. Must the prosecution produce the original of a contract to prove its terms, or is a copy admissible?
Rule. Under Rule 1002, the original of a writing is generally required to prove its content, but duplicates are admissible under Rule 1003 unless a genuine question is raised as to authenticity.
Application (model). The prosecution offers a photocopy of the contract. Because Rule 1003 admits duplicates to the same extent as originals unless a genuine question is raised about authenticity or it would be unfair, the fact that no genuine challenge to the duplicate's accuracy has been raised means the duplicate is admissible.
Pick the right element for each blank:
g1.
g2.
g3.
Conclusion. Therefore, the photocopy is admissible without the original.
MBE Check · multiple choice
P offers a printed copy of an email exchange with D, accompanied by P's testimony that he sent and received them on the dates shown. D objects on authentication. What result?
Mini Essay · write the Application paragraph
Facts. In a robbery trial, the prosecution offers a still image from a surveillance video allegedly showing D entering the bank. The original video has been overwritten by the bank's automated system. The still image is from a copy a teller saved before overwrite.
Call. Is the still image admissible?
Practice Drill · tap to build the rule
Drop the chips here in correct order:
Tap chips to add → tap chips in the target to remove: