How could Dr.Strange be sure which heroes would die?

Dr. Strange saw a single future out of many futures in which Thanos would be defeated and chose the way.

But how could he be sure who would die if they were destroyed randomly?

• I assume that the amount of futures Strange saw was due to possible death combinations. The one where they win hade certain deaths imprinted in them. – SZCZERZO KŁY Aug 23 '18 at 8:39
• @SZCZERZOKŁY: Assuming that there is no guarantee that 50% of the Avengers die (it's 50% of the population, which means it's possible for 0 or all Avengers to die). At closest proximity to Strange's stated amount of foreseen futures (14,000,605) there are 16,777,216 (2 to the power of 24) different combinations for the binary life/death state of 24 people. If Strange's decision was solely based on the death combinations, he should have foreseen an amount of futures that is exactly equal to a power of two. – Flater Oct 3 '18 at 8:12
• @SZCZERZOKŁY: That being said, I would expect the script writers to always kill about 50% of the Avengers simply to portray the 50% death toll on the population, even if it's mathematically unlikely to occur for a truly random 50% genocide. – Flater Oct 3 '18 at 8:13
• Then again Strange say that he seen 14,000,605 futures. He could stop searching when he find that one where they win. – SZCZERZO KŁY Oct 3 '18 at 8:25
• @SZCZERZOKŁY he could, but it would be wiser to try to find a few backup plans. – OrangeDog Oct 3 '18 at 10:36

The core of your question is not related to the movie, it is related to your understanding of randomness.

With contemporary scientific accuracy in mind, nothing is truly random. Everything is determined when you observe it with sufficient precision. Just because we can't predict it doesn't mean that it was therefore unpredictable.

Humans have never encountered something that was provably unpredictable, but then again, we could never be sure that we had perfect information so that we could come to that conclusion.

The result of a coin flip can be determined while it is still in the air, assuming you have perfect knowledge about the coin's weight distribution, the velocity (both linear and angular) it has, and any environmental factors (gravity, wind, magnetic interference, ...).

Therefore, even if Thanos cannot consciously control it, his selection was not random. There are two possibilities here:

Firstly, it's possible that the selection criteria were fixed. For example, let's say the infinity stones order a list of all people by their precise date of birth, and then decide to kill every second person. This guarantees a 50% mortality and it is not a biased selection.
This is not random, but to humans it will appear to be random. If someone has access to accurate ordered list of people, they will understand that the selection was not random. If someone does not have access to this list, they are unable to spot the pattern and therefore assume it was random.

Secondly, Thanos could have somehow provided a random seed. For the sake of example, let's say that he thinks of a word, and the randomness is then generated from that word. Thanos' decision, while seeming random, is not random. It is based on whatever his mind was thinking about. Therefore, Thanos' experiences influence the word he chooses.

• If Thanos ate a particularly tasty muffin during breakfast, he might remember it and therefore subconsciously pick "muffin" as the word.
• If Thanos grows fond of Tony (as he does mention he respects him), maybe he chooses "Stark" as his word.
• If Thanos feels remorse about Gamora, he may pick "Gamora" as his word.

The reasons for choosing a particular word are unknown to us and impossible to confirm. However, what we can conclude is that if Thanos' experiences are set in stone, so is the word he subsequently chooses.

For example, let's say that Thanos chooses "Gamora" as his word because he mourns for her. In that case, Strange is able to force Thanos' word choice if he's able to ensure that Thanos ends up killing Gamora, thus causing him to always pick "Gamora" as his random seed.

This means that Strange could have found a particular combination of events that leads Thanos to select a particular word, thus causing particular Avengers to survive, thus making it possible for the survivors to defeat Thanos.

• Quantum indeterminacy is a pretty obvious counter-example to your assertions. While nothing in physics can be proven to be 100% true, various hidden-variable hypotheses have been proven to be false. – OrangeDog Oct 3 '18 at 10:35
• @OrangeDog: (1) Playing the quantum physics card is unfair. That's a wholly different ballgame to begin with, and there's no reason to expect the scriptwriters of what amounts to a movie targeted at a wide demographic to specifically accurately model quantum physics. (2) Quantum indeterminacy is in no way "pretty obvious". (3) "Some options were disproven" is not the same as "it is impossible". One does not measure the correctness of a hypothesis by the amount of incorrect different hypotheses that preceded it. Most inventions/discoveries were the umpteenth attempt. – Flater Oct 3 '18 at 10:51
• That is literally exactly how you measure the correctness of a hypothesis. By disproving its counter-hypotheses. – OrangeDog Oct 3 '18 at 10:53
• @OrangeDog: That is not correct, unless you can conclusively prove that the currently known hypotheses are both mutually exclussive and perfectly complementary, so that no other possibility remains which is not already covered by the currently known hypotheses Absence of proof is not proof of absence! New hypotheses can be put forward at any time. Can we please stop arguing about both of our incomplete understandings of quantum physics and stay on topic? – Flater Oct 3 '18 at 10:55
• @OrangeDog: Not in scope of the script we're discussing here. – Flater Oct 3 '18 at 11:04

What would happened if people dead after Gauntlet effect of Thanos weren't like the future Dr.Strange saw?

Nothing would happen.

Remember that Dr. Strange saw 14,000,605 futures.

Dr. Strange: I went forward in time to view alternate futures. To see all the possible outcomes of the coming conflict.

Quill: How many did you see?

Dr. Strange: 14,000,605.

Tony: How many did we win?

Dr. Strange: One.

He chose the best path to go on which will lead them to their victory. He saw who would die and would be left after their fight. We don't know what exactly he saw yet. Maybe there were futures where the characters you mentioned were gonna die, but Dr. Strange didn't simply select it.

• This doesn't really answer the underlying core of the question: was the "50% selection" of surviving Avengers always the same for this one timeline (as seen by Strange), or could Strange not foresee which particular Avengers would survive the "50% selection"? – Flater Oct 3 '18 at 7:57