How can anyone know anything for sure if everything is subjective?

It can only be based on facts and evidence, and not emotion.

Unfortunately, humans are subjective animals.

Everybody has different experiences and perception about what they see, and how they interpret it. No two humans have the same experience or perception.

Ever sat in a court, and listened to witnesses, and how they can interpret the same event differently?

That’s one of the best examples, of how humans interpret the same event differently.

I sat in on a murder-rape trial in Santa Clara County Court some years ago in the jury. It was one of the longest trial in our county, that lasted three months. Many didn’t have direct eye witness of the murder and rape, and everything was based on circumstantial evidence. Our jury found him guilty. He’s now spending the rest of his life in prison, without the possibility of parole.

Wouldn’t you call that, subjective evidence?