This is my first post in philosophy.stackexchange, so hello! First, I would like to ask whether the audience thinks my question below is appropriate here, or if it is merely an opinion question. To me, it seems like an interesting moral dilemma, but if you all disagree please let me know.

Imagine that you are a victim of a crime perpetrated by one individual. Let's say that crime has a minimum punishment of 50 years in prison, and a maximum of life in prison. Assume the criminal slipped up for a moment during the act, allowing you to make out the general features of his or her face and body structure. You file a police report, including the description of the perpetrator so a sketch can be made. A few days later you get called down to the local police station to try and identify the criminal from a lineup of five suspects they have brought to the station. After looking through the lineup closely from behind the cover of a one-way mirror, you believe you can identify the correct person as the criminal. Let's say for the sake of this thought-experiment that the probably of your choice being the correct one out of the five people in the lineup is 65%; on the flip-side the probability of choosing incorrectly is 35%.

a) Given these probabilities, and the punishment range for the crime, would you name the person you think as the criminal and press charges, risking sending the wrong person to prison? Why?

b) Would your answer to the above question differ for the lineup being of men as opposed to of women? Why?

c) If your answer to the first question was no, what probability of success would you need for you to name the individual as a criminal?

d) Would the answers to any of the above questions differ if you were not behind a one-way mirror, but instead standing directly in front of the lineup, and had to name the individual to his or her face?

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    Welcome to philosophy.se. This question doesn't seem well-suited to the format here. It's too open-ended.
    – virmaior
    Commented Oct 1, 2014 at 6:06

2 Answers 2


Such line-ups are populated by one police suspect and others who are not under suspicion. The purpose is not to decide who is the suspect, but to provide strong corroborating evidence for use in court.

If the victim wrongly identifies a non-suspect, they do not become a suspect. Indeed, in many juristictions, "fillers" are taken from the prison population - all of whom have a strong alibi of being in prison at the time!

In all cases then, the ethical act is to be as honest as possible.

Allowing the suspect to see the victim is unfair to the victim. Nowadays several police forces use video footage as the basis of the identity parade so that there's no need to have them in the same place at the same time.


To add to @AndrewC's answer (which I think is quite correct BTW): I would certainly pick any person out of a lineup if I thought with 65% probability that it was the correct person. That person is not necessarily going to be convicted of the crime in question, they still must stand trial and be found guilty beyond any reasonable doubt.

I would, however, tell the police how sure I believe myself to be when/if I pick someone out of any lineup. Even if I were 100% sure, I would still say "I am 100% sure" rather than simply point the person out silently with my finger.

The only thing that would keep me from choosing is if two people in the lineup were fairly close. Lets say that two people looked similar: I would tell the police that those two look really similar and I cannot confidently choose one over the other, but that I think it is possibly either one of those two. The police may not like that answer, but it would be the truth.

To your point about any difference between men and women: no, not one difference to me. Picking faces out of a lineup is picking faces out of a lineup.

To your point about picking someone out face to face: that is a whole different thing. It depends on other factors like does this person have a reputation of killing witnesses and/or their families? That is a whole separate topic all together, to which I have no good answer for.

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