Skip to content
Coordinates of ThoughtHome of Philosophy
Join
Discussion

“I know what I saw”: what is a witness actually claiming?

Sana Rizvi Fellow
· 6 replies
Evidence & testimonyAnalyticGreek & RomanIslamicElizabeth LoftusIbn al-HaythamPlato#courts#eyewitness-testimony#memory#perception
Follow

I cover courts and human rights in Karachi. The sentence I hear most often in witness boxes is "I know what I saw." It's said with total conviction, often by people who are mistaken.

Psychologists have shown how fragile this is. Elizabeth Loftus's experiments in the 1970s found that changing a single word in a question, asking how fast cars were going when they "smashed" rather than "hit", changed people's estimates of speed, and made more of them remember broken glass that wasn't there.

So what is the witness claiming? I see three possibilities:

  1. A report of perception: I saw it, and seeing is knowing.
  2. A report of memory: I remember seeing it, which is a different and weaker thing.
  3. A report of certainty: I feel sure, which is a fact about the witness, not the event.

Courts often treat the third as evidence of the first. I don't think it is. I'm curious what philosophers, lawyers and scientists here make of it, and whether older traditions noticed the problem before psychology did.

LikeReply
Follow6 replies

Join the conversation: members reply here, and joining is free. Reading is always free.

Join free to reply Sign in

6 replies

  1. Khalid Mahmood Awan

    Fellow

    Thirty-one years of watching trials taught me that confidence and accuracy are almost unrelated in a witness box. The confident witness is often the one who has told the story most often, to the police, to the family, to the lawyer, and each telling polishes it. Our law of evidence requires the court to assess a witness's credibility, and the best judges I watched always looked for the details that didn't fit the story the witness wanted to tell. A memory that has been rehearsed into smoothness is less trustworthy, not more.

  2. Layla Sfeir

    Fellow

    Ibn al-Haytham is the obvious older source. His Optics has a long treatment of errors of sight: how distance, light, the time of viewing, the condition of the eye and prior expectation can each produce a mistaken judgement, even when the eye is working perfectly. His key insight is that seeing involves judgement and inference, not just reception. So "I know what I saw" was, for him, already a compound claim: something affected the eye, and the mind judged it to be such-and-such. Error enters at the judging.

    Helpful · 1
  3. Priya Raghavan

    Fellow

    From cognitive science: memory is reconstructive. Each time you recall an event, you rebuild it, and the rebuilding can incorporate later information. So option 2, the report of memory, isn't a report of a stored recording; it's a report of the latest reconstruction. Khalid's point about polishing is exactly what the research predicts.

    Helpful · 2
  4. Titilayo Adeyemi

    Fellow

    In Yoruba, as I mentioned in another thread, the verb for "know", mọ̀, is tied to first-hand witnessing. That might seem to make witness claims stronger. But elders I've worked with are also very careful to ask how someone witnessed: in what light, from where, with whom. The language gives first-hand experience high status and then insists on interrogating it. That seems to me the right combination.

    Helpful · 3
  5. Andrés Zuluaga

    Fellow

    Something from Colombia's truth commission complicates option 3. When victims testify, their certainty is often about the meaning of what happened, not its details. A woman may misremember the date, the colour of the truck, the number of men, and be completely right that her son was taken. Courts that discredit the whole testimony because of a wrong detail make a philosophical mistake: they treat knowledge of the core as if it depended on knowledge of the periphery.

  6. Sana Rizvi

    Fellow

    This is what I hoped for. Ibn al-Haytham's "error enters at the judging" and the research on reconstruction explain why my option 3 is so misleading. Andrés's point I'll carry into my reporting: a witness can be wrong about the truck and right about the son. Plato had the jury example in the Theaetetus, true judgement without knowledge, but this is the reverse: knowledge of the core surrounded by mistaken detail. I'm not sure the classic theories handle that case well.

    Helpful · 1