No one is ever truly appreciated until it's too late and they are long gone. Many prominent historical figures who changed the course of science and culture were labeled heretics and nut jobs but once they were laid to rest people realized they were a little hasty in their opinions.
Redditor u/ImEnhanced wanted to make a list for all to make themselves aware of some history lessons asking... Who in history turned out to be right after they died, but were called crazy while they were alive?
Major General Pendleton. He was black balled and ruined his career after WW1 for believing the Japanese were fortifying pacific islands with plans to attack the U.S. fast forward 20 years and the marines fought some of the toughest battles trying to dig out super fortified Japanese soldiers. Waffles_N_Tiddys
The Anit-Tabacco King!
King James I of England gave a formal statement in 1604 expressing his distaste for tobacco, claiming that it is "hateful to the nose, harmful to the brain, [and] dangerous to the lungs," basically everything that we tell people about cigarettes now. it was called "A Counterblaste to Tobacco." whether people didn't believe him or just didn't care can be debated. zmm336
Told you so...
The Japanese mayor who, in the 1970's, built a huge seawall to protect the town from tsunamis. He died with being mocked his whole life. But ended up saving everyone in the 2011 tsunami.
Tsunamis are terrifying and no one likes thinking about them (more specifically, the things associated with them, death and destruction, lost of loved ones and homes).
Kinda like how people often get angry at victims (whether they can be reasonably faulted for anything at all or not) because feeling bad for others, feels, well, bad. Therefore "if only the victim hadn't been victimized, I wouldn't feel bad right now" (for them of course and because bad things happen), so "if only the victim had done something differently, I wouldn't feel bad," and thus "it's your fault that I'm feeling bad."
Though whether it's mocking the aforementioned Japanese guy or victim-blaming, it must be a series of illogical leaps, making it hard for rational people to relate to... DMinyaDMs
Hold the feces please...
Not so much crazy as gross, but Dr. John Snow figured out that cholera is water-born and laid the groundwork for modern epidemiology. However, given that his finding was that a massive cholera outbreak was caused by water contaminated with feces, people weren't keen to accept his conclusions and it took some time for them to be completely accepted. IThinkThingsThrough
Save the babies...
Ignaz Semmelwies, beaten to death in an insane asylum after the scientific community ridiculed him and locked him up.
He suggested that washing hands before delivering babies might be a good idea. (At the time it was known gentlemen didn't have dirty hands). SpartanThane
So the Doctor would perform a surgery, wipe his hands on his apron, then walk into the next room to deliver a baby with the blood, bacteria, and germs of the surgery patient still on him. No hand washing in between. This not only lead to a high infant mortality rate, but also lead to the deaths of many of the mothers (1. his hands were inside her and 2. she would have lacerations around her vaginal area that could get infected). maznyk
Too Infinity and Beyond...
He changed the fundamentals of mathematics by inventing set theory.
He proved that there are different sizes of infinities. And he was criticized and ostracized by many, but not all, of his peers for it. As a result, he suffered from depression and spent the last few years of his life in an insane asylum.
But he was right. jimmy_rigger
But the basic gist is like this...
Take the set of natural numbers (1, 2, 3, 4, 5.... on to infinity), and say, the set of even numbers (2, 4, 6, 8, 10...) Now, on it's face, it looks like there's more naturals than evens, so its a natural (no pun intended) question to ask "hey, is there something to that?"
But, after some thought you maybe realize "Well, if I could sort of wave a magic wand over the naturals... a magic wand that has the magical ability of 'multiply by 2', then I'd get the set of all evens. I wouldn't have to take anything out of the set of naturals. My wand doesn't REMOVE anything. It just modifies everything." And then you can conclude that at least in some sense, there's the same "amount" of evens as there are naturals... despite the fact that the evens are perfectly contained within the naturals.
So, then you think "What about the naturals vs the RATIONALS (aka fractions). In between any two natural numbers, there's INFINITELY many rationals, so maybe there's distinctly more rationals than there are naturals?"
(And this is where I'm going to start leaving out details, that maybe someone with more patience than me will fill in for you).
But, it turns out that there's a fairly clever trick that you can assign to a magic wand, such that when you wave it, you can turn the set of naturals into the set of ALL of the rationals (both positive and negative). Which means, you can start with the set of naturals, and, without inserting or removing anything into the set... soley by modifying each element... You can convert that set into the set of ALL rationals. So this suggests, once again, that the set of naturals and the set of rationals have the same "amount" of stuff.
This starts getting to be quite the head-scratcher, and perhaps leads one to believe "Well, infinity is just infinity and that's all there is to it. You can get from any infinite set to any other infinite set by waving a magic wand with a suitably clever rule."
But Cantor proved that that's most definitely NOT the case. In particular, he proved that there's no possible magic wand whatsoever that can convert the naturals into the set of ALL real numbers. (The set of reals includes all the rationals, as well as all the irrationals like pi, and e, and all manner of square roots, and cube roots, and myriad other stuff that I quite literally couldn't ever possibly describe).
Further, he also proved that if you give me any infinite set, I can construct, from that set, an even BIGGER set. And that I can do this on and on and on, constructing infinitely many sets of all sorts of different sizes of infinity.
And that's my best effort at an ELI5 that you didn't ask for. angryWinds
The original Rocketman...
Guy who invented Rockets. He was laughed at because people thought rockets can't propel in space because there is nothing to push against. He died before the first rocket went in space.
New York Times practically laughed on his work and called that he can't even understand newton's law of motions in editorial, only to publish correction 49 years later when he was long dead.
Edit: rockets in space, i.e. space travel. iamelectron
The Atom is the key...
Ludwig Boltzmann. He proposed the existence of atoms, everyone called him crazy and thought he was wrong. He hung himself in 1906 as a result, only for scientists to prove the existence of atoms three years later. owen00600
I heard they also didn't believe him about entropy. The equation S = k logW is literally written on his grave. StopBarkingAtMe
The Water Giver...
C. Y. O'Connor was an engineer who designed a 530km (330 mile) long pipeline to provide water to Kalgoorlie from Perth in Western Australia. He was berated by the public for it and ended up shooting himself while riding his horse before the pipeline was commissioned.
It is still providing water to Kalgoorlie to this day. Skorne13
And apparently doing a damn fine job. Google maps shows that the town, seemingly in the middle of a desert, has tons of green spaces, plenty of people (speaking relatively), and enough water for lawns (which I dislike) and lots of trees (which I like).
That town may not have existed/survived without O'Connor's pipeline idea. Apparently it is in the Gold Fields, so money was probably more easily spent on such a project, especially once the riches started to pour in. WagTheKat
Your local weatherman...
Alfred Wegener about his theory regarding the movements of continents. fakiessss
The thing that has to be noted about Wegener is that he not only proposed a theory that would have seemed completely insane to anyone at the time (what'd'ya mean the continents move?) but he was also a meteorologist by profession and was trying to tell geologists that everything they knew about geology was wrong. It would be like if a botanist popped up one day and said "hey, I figured out the unified field theory of physics and it completely undermines a lot of what you thought you knew about physics!" schnit123