Two ranks occupy the same pay grade in the U.S. Army, the specialist and the corporal. The difference between the two isn't always as clear to other members of the military from other branches.
In short, the difference between the two E-4 grades is that one is considered a non-commissioned officer while the other is not. The corporal will go to the NCO training school while the specialist might not. In practice, the corporal outranks a specialist and will be treated as an NCO by the soldiers below him or her. The specialist is still an E-4 level expert at his or her MOS.
That's why a specialist is also known as a "sham shield" — all the responsibility of a private grade with all the pay of a corporal. Now that you know the gist of the difference, you'll see why this Quora response is the best response ever — and why only a veteran of the U.S. Army could have written it.
When someone on Quora asked about the difference between these two ranks that share a pay grade, one user, Christopher Aeneadas, gave the most hilarious response I've ever seen. He served in the Army from 1999-2003 in signals intelligence. Having once been both a specialist and a corporal, he had firsthand knowledge of the difference, which he describes in detail:
A Full Bird Private has reached the full maturity of a Junior Enlisted Soldier. That magnificent specimen is the envy of superiors and subordinates alike.
The Sham Shield is the mark of the one who has taken the first steps toward enlightenment.
The Specialist knows all and does nothing.
The first two Noble Truths of Buddhism are:
The First Noble Truth - Unsatisfactoriness and suffering exist and are universally experienced.
The Second Noble Truth - Desire and attachment are the causes of unsatisfactoriness and suffering.
The Full Bird Private understands that to cease suffering, one must give up the desire to attend the Basic Leader Course (BLC).
A soldier can live for many years in harmony with his squad and his command if he simply forgets his attachment to promotion. There is wisdom in this.
In the distant past, there were even greater enlighted souls. Specialist ranks only whispered of today: Spec-5s and Spec-6s. Some even reached the apotheosis of Specialist E-7!
Mourn with me that their quiet, dignified path is lost to soldiers today.
The Corporal is a soldier of ambition.
They have accepted pain without pay.
They have taken duty without distinction.
Whether they are to be pitied or admired is an open question. I take it on a case-by-case basis.
They hung those damned chevrons on me unofficially for a time. I guess they caught on that I liked my Specialist rank a bit much.