Finding common ground
It’s impossible to reason with anybody unless you already agree with them about something. Before any argument can have any effect on another person, they must agree with the premises. If they don’t already agree with the premises, then you have to begin with more basic premises that they do agree with.
Sadducees only accepted the first five books as scripture. They did not recognize the writings and the prophets as scripture. Since resurrection was not in the Torah (the first five books), they rejected resurrection. There are three explicit references to resurrection in the Old Testament—Daniel 12, Isaiah 26, and Ezekiel 37. When Jesus debated with the Sadducees about the resurrection, he didn’t quote any of these passages. Instead, he quoted from the Torah. Jesus began with something the Sadducees already agreed with, and he made his case from that premise.
Paul did the same thing when speaking at the Areopogus. Since the Greeks he was speaking to didn’t accept any of the Bible as scripture, Paul didn’t begin with the Bible. Rather, he began with an idea they already accepted. He pointed to a statue dedicated to an unknown god, and argued from there to the true God.
This procedure makes all the sense in the world. If a person doesn’t accept the authority of the Bible (or some part of the Bible), then it doesn’t make sense to appeal to the Bible (or that part of the Bible) in order to make your case to that person. You have to do it some other way.
It’s a good idea, when you’re arguing with somebody, to find out a little about what they believe and why they believe it. Rather than come out swinging with your arguments, ask them questions instead. Feel them out a little. Not only will this put you in a better position to reason with them, but it’s also a lot less off-putting than mowing them down with your arguments from the get-go. Of course when you're asking the questions, you have to be careful not to turn it into an interrogation. That's also off-putting. Once people are on the defensive, all listening has stopped.