In order to reach agreement, you must first know what the disagreement is about. There are five types of disagreement, best illustrated with a contempoary example.
Disagreement about definitions
"Climate change is a long-term change in the average weather patterns." "Climate change is the long-term heating of Earth’s climate system"
Disagreement about facts/indicators
"The data indicate that climate change is happening."
"The data show a natural variation in global mean surface temperature."
Disagreement about causes
"Climate change is caused by human activity, e.g. anthropogenic emissions of greenhouse gases ."
"Climate change is caused by natural processes, e.g. increased solar output."
Disagreement about goals/consequences
"Climate change will have detrimental consequences for all of humanity."
"Climate change has a positive effect on primary production."
Disagreement about actions/preferences
"In order to curb the effects of climate change, we must introduce a carbon tax on fossil fuels."
"In order to curb the effects of climate change, we must plant trees."