I don't understand Hadith Science

[pirater]

I saw a thread and a guy quoted a hadith which a man born in the 1800s stated that it is a credible source. What I don't understand is that how does a man born in the 1800s know if a source is credible when the Prophet Muhammad (SAW) was born a millennia earlier. I am just trying to better understand the science of how we can tell if a scholar is credible. Could someone please explain. Jazāk Allāh

 

[The alchemist]

To judge if someone is credible, one has to be fairly knowledgeable about the discernment processes to be able to distill if at all anything is false and then review based on the rich literature.

 

[Leeban]

he’s discerning the chain of narrators, the prophet is authentic but you have to study the the chain to see weaknesses in either timing character of narratives, when the prophet said it, context, ect ect it’s a actual discipline