A civilisation eventually advances enough to have laws. Once that happens, some person who is not literate or not clever, or both, needs the help of someone who is, a champion to fight for him, against some person who is literate and clever but in the wrong. Then you have lawyers.
Your studies may lead you to the discovery that, until the 1890s, no defendant could testify (give evidence as a witness in court) in his own defence in this country. There was fierce argument about this. Why? Because it was thought manifestly unjust to expose a man who was not intelligent or worldly wise, yet innocent, to being cross-examined by some highly educated , clever man who would make him appear guilty. It was a mismatch. That is applying, in fairly modern times, and rather intensely, the principle in my first paragraph here