Quote - >> Answer = transistor <<

Please be clear: are you stating that the engineers and inventors at Bell who came up with the transistor actually had to have a high-theoretical understanding of Quantum Mechanics in order to succeed, and that if QM had not developed as a theory in the years prior to the 50s that creating the transistor would have been impossible?

Notice: I am not asking if QM is how a transistor works at a primal level; I am only asking if the Bell people need to know and understand the explicated theory in their work.

::::: Opera :::::

Transistor was invented by Shockley and is a direct consequence of Quantym theory, without QM it was impossible to make it. Contrary to most inventions the transistor was a theoricaly planed invention, the theory of a transistor existed before it physically existed, is just the opposite of he valve.
A valve or tube was a result of empirical work, walves existed, were used and nobody knew well how it worked, only Quantics was able to explain the valve. Quantics explained the valve, but wasn't needed for its creation and use.
Transistors were invented in the paper and are a direct consequence of the application of Schroedinger equation to a semiconductor. Without Schroedinger no way to know that a juctoon needs two semiconductors contaminated by a small amount of impurities and the ammount of them, well also no way to know a junction itself.
The problem was to make the transistor something usable and reliable, it was a technological problem, the first transistors were very fragile. The firsr commercial transistors were made of Germaniun, Silcon and other semiconductors were known, but Germanium was superior to Silicon and in those days no technology to do something with Silicon that only was used long years after. Silicon is inferior to Germanium, but it resists much higher temperatures, is strong mechanicaly, can be grown and contaminated in a very controlled way and suitable for integration. Also exist from the begining other semiconductors as Gallium-Arsenide, the electron has a very high mobility that allows it to be very much faster than Silicon, but still today there's no technology to use it as we use Silicon, so GaAs applications are limited to simple device as microwave diodes or laser diodes.

Quote - So kawecki I know you intended your statement that Einstein is the Aristotle of the 20th century to be an insult. However, your unintended consequence is to praise with the highest praise.

The problem is not Aristotle nor Einstein, the problem is people that elevated them to God.
Aristotle was a great Greek philosopher and he produced an extense work, ideas and concepts, some were correct and some were wrong.
Aristotle created, probably imported the idea from China, the theory of the four elemnts, a nice , and brilliant heory to explain Nature, some other Greek had the atom theory, but it was not so nice and brilliant. Fine, no problem, one more theory among others.
The problem was that people of middle-age picked Arsistotle's work as the most absolute truth, the other theories, conceptions, ideas, philosophers were plain and simple ignored if not had their work destroyed.
Nobody was allowed to contradict Aristotle, he turned God, no matter if what was observed didn't matched what Aristitke said, he was the tryth and only truth. If someone had another idea, theory or conception, no matter how this matched with the observation, he was ignored and ridiculizsed.
The result is obvious, if you base on a wrong theory no matter if you insist one thousands years with this theory the result always will be wrong and no progress made in those thousand years, in another words, the dark-age.
With Einstein is the same, Einstein had an idea, a concept and made another nice and brilliant theory, his theory explained some things that had in those days no explanation, the same happened with Aristitle in Greek times, the four elements explained many things.
In the same way as in Greece Aristotle made his four elements theory some another guy that nobody remembers his name made the atom theory.
In the XX centurty happened the same, Einstein's made his theory that explained many things, other guys that also nobody remebers their name, made another theories to explain the same.
Einstein was elevated to God and his theory is the most absolute truth, it is impossible to something travel faster than light, it's a dogma and the most absoulte truth, if someone makes a theory that contradicts this dogma no matter how this theory explain many things without explanation, he is ignored and ridiculized and have to wait for the year 3,000 to be discovered again.
There is a huge number of experiments and observations that contradicts Einstein theory, experiments and data that shows that gravity is not what Einstein said, all this that are giving a clue about Nature of something to be researched and discovered is ignored and no progress is made.
For making it worst, Einstein turned into the greatest Genius ever existed, but people said that he was a genius because someone or the media told them that he was a genius and not by taking his work, analyze and the say, "this is brilliant", people repeat only as parrots, there are few people that know his theory, but everybody tells that is the greatest theory.
Greatest in what?, how do you know if is great or a trash if you know nothing about it, you are not able to understand a simple equation,  by the same logic Chinese must be genius, I don't undertand a single painted Kanji.
Only when you know and are able to understand the theory you can say, is good, is bad, I agree, I disagree, he was a genius, he was a dedicated student or even he did nothing and copied the work of another person.

And for the end another clue:
Einstein's theory is a four dimensions theory, we had always three dimensions and Einstein introduced time as the fourth dimension, a great improvement that caused great admiration among people and a nice mathematical construction.
Now we live in an Universe with four dimensions, fine, but did you know that time in Einstein's theory is imaginary and not real?
Time is imaginary!!!, a nice mathematical construction. but it doesn't represent the real world, imaginary numbers only exist in the mind.

Stupidity also evolves!