I am writing a detective story where one of the detectives can read people's minds; however, as this cannot be used in court they need a machine that can a) record and visualize an individual's thoughts, and b) differentiate between mundane thoughts and thoughts that an individual will actually do.

However my conundrum is that if a machine could do these things, then what would be the point of the Telepath in the first place?

My idea was that the Telepath can read thoughts and memories and is able to 'pull' these memories to the surface or conscious, but the machine can only read thoughts; what an individual is currently thinking, but cannot read memories. So, a non-telepath wouldn't be able to use this machine as they would have no idea how to navigate an individual's mind.

Do you think this makes sense or not? Any ideas are welcome.

  • $\begingroup$ I totally agree who needs a clerk when I got computer... $\endgroup$
    – user6760
    Commented Nov 26, 2019 at 12:06
  • $\begingroup$ Does a typical target know that his mind is being read by a telepath when it happens? What about if the machine does it, if the machine is disguised or concealed? $\endgroup$
    – notovny
    Commented Nov 26, 2019 at 16:39
  • $\begingroup$ How much effort and how obvious does he have to be to read these thoughts? I mean...he's a detective and not everyone would be willing to hook themselves up to such a machine in front of him. It's similar to how the existence of guns doesn't make being able to shoot deadly projectiles from your fingers obsolete since you can't always take a gun with you everywhere. $\endgroup$
    – DKNguyen
    Commented Nov 26, 2019 at 20:12
  • $\begingroup$ Why did we bother with ears when we can transcribe conversation and read it later? $\endgroup$
    – SRM
    Commented Nov 27, 2019 at 5:29

6 Answers 6


A telepath is a craftsman. Diffrence is like with custom made suit made by tailor and store bought one.
Machine record is crude, thought and feelings and "visuals" lack crispiness. Sometimes the are contained with other thoughts "I will kill Jon Doe tomorrow, Tomorrow Bet your bottom dollar That tomorrow There'll be sun!" .
Machine need a validator. So in a room full of people there need to be someone who would validate that it was John Smith thought and not someone else. (If you're plannign to commit a crime think in other language than your native one).
Machine is a machine, you might become "aware" of it's working by having your thoughts suddenly dissapear "lost track of my thought". Or you don't want to think about something yet something is pushing you to do that.
A telepath (and skilled one) can easily go into discourse with you pretending to be your selfconciousness. They can wait for the thought to appear and then encourage you to unravel them "I thought about killing Joe Doe. First time I had that thought was when I saw him murdering all those kids in back alley. Then he throw me into asylum and used my family money to become the mayor".

So a machine would be fine to find if any of the passengers is constantly thinking about that bomb he have in his pocket. A telepath would know who give it to them, what they looked like, where t was, do they know how to defuse it and so on.


The distinction between living telepaths and memory viewing machines is comparable to having a conversation vs reading a script. The machine queries the subject's mind and receives a response. The telepath interacts dynamically with the subjects mind, choosing each new query based on subtle aspects of the previous response. A telepath can bring nuance and intuition into the process where a machine can only follow its script.

In theory, a skilled operator could mimick a good telepath, choosing each next scripted question only after viewing the previous reply, but the process would be much slower and the subject would have much more time to plan their replies because of the time needed to view the previous reply and then enter the next question.


Detectives' gut instinc leads the investigation.

Your police officer knows sweet granny Elizabet poisoned her grandkid and now he searches for proof.

Knowing your suspect IS the bad guy lets you focus your attention on it instead of chasing 40 probable suspects.

Only 1 house to search instead of 40. Only 1 search warrant is really likely to be approved.

This is a boon any detective would give an eye for!

  • 1
    $\begingroup$ This is common in detective work, quite often they'll have several leads, and inadmissible evidence or hearsay can prove invaluable at informing where to focus your investigation in order to gather harder evidence. $\endgroup$
    – Archerj
    Commented Nov 26, 2019 at 12:04
  • $\begingroup$ If the Detective can get a search warrant and, while they are going over the kitchen, your suspects thinks "Got lucky, they never checked the dog food." Now that bag is relevant. $\endgroup$
    – Gustavo
    Commented Nov 26, 2019 at 13:58

The Machine is Large and Expensive

Basically, the machine is like a supercomputer. Their size makes them completely stationary and as they are expensive to build, time on them is at a premium and needs to be applied for. There may also be a significant backlog on getting time on the machine, and there's certainly a lot of paperwork involved.

So from a department's perspective the telepath is a cheaper, portable version of the machine they can deploy at will.

  • 1
    $\begingroup$ To add to this, I would imagine simply having a telepath lead an investigation is much more likely to turn up tangible evidence, while I imagine the machine would only be permitted to be used on someone who has already been arrested and/or a warrant is served. $\endgroup$ Commented Nov 26, 2019 at 17:11

Organic Memories aren't accurate representations of the facts

Latest research into how memories work shows that when someone remembers something, their brain is re-experiencing it and taking notice of what they choose to at that present and their brain's current context.

This has huge ramifications for memory because it means that memories aren't entirely infallible, and due to the fact the memory is being re-experienced, something minute is changed every time.

You see this all the time with acceptance of trauma and coping with difficult memories, or trying to rectify the memory of something someone particularly feels bad about. They'll often unconsciously make minute changes to other parties' intentions or even situations, maybe add more context, in order to frame themselves more sympathetically (the human brain is hard-wired for optimism, to cause itself less pain). This is how people eventually over time learn to accept traumatic events in the past, and is a pattern often seen in murderers trying to live with their actions.

If a memory machine can capture a memory in one form, it is less susceptible to how the rememberer's current brain state can bias the memory. However, if you have an older machine-based recording of the memory, and take a current sample, you can notice biases that a person is unconsciously adding to their memories.


Because it gives you information

For example, you may have a murder investigation. Reading the murderer's mind can lead you to the exact patch in the forest where he buried the body, so you can exhume it and search for clues, where any other detective doesn't have access to those clues.

You can read the minds of the drug couriers, you'll never have to pull someone out of the airport line that isn't guilty, but you'll catch all the real couriers. And you'll know exactly where they have the drugs, so you can prove it easily.

(I am aware that there are methods to smuggle drugs that use unaware couriers - but there's still plenty of aware couriers that this would have incredible value.)

TL;DR: Just reading the actual criminal's thoughts can help you find evidence.


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