Whenever Spock appears, he always brings logic. However there is a difference between logic and omniscience. Clearly Spock doesn't know everything, otherwise you wouldn't need Scottie, Bones or most of the crew. He could run the Enterprise on his own apart from needing Kirk who usually defies logic in order to win.


If Spock reads so widely and knows so much, how come he doesn't know more about other crew members' jobs than they do themselves? Presumably if he did know more than them, he wouldn't have enough tact to hide it.

Are there any stories in the whole of Star Trek where Spock (a) gets his facts wrong unknowingly, (b) admits to being ignorant of something when asked a question, (c) uses or states faulty logic?

  • 3
    If you ask Spock, he's always logical and correct. "Spock: Quite simply, Captain. I examined the problem from all angles, and it was plainly hopeless. Logic informed me that, under the circumstances, the only possible action would have to be one of desperation. Logical decision, logically arrived at." From The Galileo Seven
    – Jaydee
    Jul 29, 2015 at 8:48
  • 4
    Logic does not equal all-knowing. You can take every logical step to accomplish a task, but if you lack the proper knowledge, you're just using educated guesses. Jul 29, 2015 at 15:38
  • I was very tempted to just answer with "Yes", but I wouldn't be able to emotionally handle the avalanche of downvotes I'd get.
    – Liesmith
    Jul 29, 2015 at 18:19
  • 1
    "Scotty," not "Scottie." May 1, 2016 at 15:58

3 Answers 3


Star Trek’s Mr. Spock is not the exemplar of logic and rationality. Instead, he is a “straw man” of rationality used to show that human emotion and irrationality are better than logic.

His role is to show that emotion and irrationality is superior. He gives extremely exact probabilities which never pan out.

Being better at decision-making than Spock is like being able to beat up Worf.



What your Vulcan could sound like if he wasn't made of straw:

"The spatial anomaly has interacted with the tachyonic radiation in the nebula, it's interfering with our sensors. It's impossible to get a reading."

"There's no time - we'll have to take the ship straight through it!"

"Captain, I advise against this course of action. I have calculated the odds against our surviving such an action at three thousand, seven hundred and forty-five to one."

"Damn the odds, we've got to try... wait a second. Where, exactly, did you get that number from?"

"I hardly think this is the time for-"

"No. No, fuck you, this is exactly the time. The fate of the galaxy is at stake. Trillions of lives are hanging in the balance. You just pulled four significant digits out of your ass, I want to see you show your goddamn work."

"Well, I used the actuarial data from the past fifty years, relating to known cases of ships passing through nebulae that are interacting with spatial anomalies. There have been approximately two million such incidents reported, with only five hundred and forty-two incidents in which the ship in question survived intact."

"And did you at all take into account that ship building technology has improved over the past fifty years, and that ours is not necessarily an average ship?"

"Indeed I did, Captain. I weighted the cases differently based on how recent they were, and how close the ship in question was in build to our own. For example, one of the incidents with a happy ending was forty-seven years ago, but their ship was a model roughly five times our size. As such, I counted the incident as having twenty-four percent of the relevance of a standard case."

"But what of our ship's moxie? Can you take determination and drive and the human spirit into account?"

"As a matter of fact I can, Captain. In our three-year history together, I have observed that both you and this ship manage to beat the odds with a measurable regularity. To be exact, we tend to succeed twenty-four point five percent more often than the statistics would otherwise indicate - and, in fact, that number jumps to twenty-nine point two percent specifically in cases where I state the odds against our success to three significant digits or greater. I have already taken that supposedly 'unknowable' factor into account with my calculations."

"And you expect me to believe that you've memorized all these case studies and performed this ridiculously complicated calculation in your head within the course of a normal conversation?"

"Yes. With all due respect to your species, I am not human. While I freely admit that you do have greater insight into fields such as emotion, interpersonal relations, and spirituality than I do, in the fields of memory and calculation, I am capable of feats that would be quite simply impossible for you. Furthermore, if I may be perfectly frank, the entire purpose of my presence on the bridge is to provide insights such as these to help facilitate your command decisions. If you're not going to heed my advice, why am I even here?"

"Mm. And we're still sitting at three thousand seven hundred to one against?"

"Three thousand, seven hundred and forty five to one."

"Well, shit. Well, let's go around, then."


  • 5
    Wish i could give you more than just +1 with an upvote
    – atk
    Jul 29, 2015 at 15:25
  • @atk In case anyone sees this years later: you can award a bounty.
    – Davislor
    May 22, 2019 at 19:03

I will say yes, Spock is fallible. Everybody is fallible.

Spock is a brilliant scientist and a very good Starfleet officer. He is a very useful member of the crew. But knowing enough to do everyone's job is a crazy idea. It would be impossible for Spock to know all the technical knowledge required for half a dozen different Starfleet jobs and also all of his scientific knowledge. And of course Spock can't be in a dozen places at once so he can't do everyone's job at the same time.

Like all people, Spock sometimes fails at his job. For example, in "Journey to Babel" The Enterprise is stalked by a mysterious alien vessel while Spock's father Sarek needs Spock to donate blood for Sarek's life saving operation. The wounded Kirk tricks Spock into giving up command to save his father's life.

SPOCK: Captain?

KIRK: I'll take over, Mister Spock. You report to Sickbay with Doctor McCoy.

SPOCK: Captain, are you quite all right?

MCCOY: I've certified him physically fit, Mister Spock. Now since I have an operation to perform and both of us are required

KIRK: Get out, Spock. Chekov, what's the status of the intruder?

Spock is convinced too easily that Kirk is well enough to command.

Later in Sickbay:

CHAPEL: Mister Spock.

(Spock is starting to get up.)

MCCOY: Where do you think you're going?

SPOCK: I must see the captain.

MCCOY: My patients don't walk out in the middle of an operation.

SPOCK: The alien ship. I've just realised that if their power utilisation curve is not the norm, it should be possible to identify them this way. Very important.

(Chapel gives him a hypo to put him to sleep.)

MCCOY: So is your father's life.

And later:

SPOCK: Captain, I believe you'll find the alien

KIRK: We damaged their ship. They destroyed themselves to avoid capture. Bones, Thelev's body will be brought to your lab. I want an autopsy performed as soon as possible.

SPOCK: I think you'll find he's an Orion, Doctor.

MCCOY: Orion?

SPOCK: Intelligence reports that Orion smugglers have been raiding the Coridan system.

KIRK: But what would they gain by an attack on Starfleet?

SAREK: Mutual suspicion and interplanetary war.

KIRK: Yes, of course. With Orion carefully neutral, they'd clean up supplying dilithium to both sides and continue to raid Coridan.

SPOCK: The thing that confused me was the power utilisation curve. It made them seem more powerful than a starship or anything known to us. That ship was constructed for a suicide mission. Since they never intended to return to their home base, they could use one hundred percent power on their attacks. The thing I don't understand is why I didn't think of it earlier.

KIRK: You might have had something else on your mind.

SPOCK: That hardly seems likely.

KIRK: No, but thank you anyway.

Spock may refuse to admit it, but if he hadn't been worrying so much about his father he would have figured out the situation before Kirk relieved him and the information could have been very useful for Kirk during the battle. So this is an an example of Spock's fallibility making him less effiicent than he should have been.


A direct example of Spock's fallibility occurs during the episode 'Tomorrow is Yesterday' (right name?). They pulled a jet fighter pilot out of his jet with the transporter, then they believe they cannot return him because he has seen too much. Spock says that he has researched the pilot's life in the ship's records, and has concluded that his absence will not change history significantly. A chance remark later makes Spock realize he has neglected to consider the impact of the pilot's offspring; it turns out the pilot's son (not yet conceived!) has been recorded in history as commanding the first manned Mars mission, so the pilot DOES have to be returned.

  • 1
    Whilst a nice answer this would be greatly improved by editing in the relevant quotes from the episode you are referring to.
    – TheLethalCarrot
    Aug 12, 2019 at 13:46

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