A poll cited by Reason's Volokh blog found that nearly half of Palestinians in the West Bank do not believe Israel has a right to exist. That result, taken at face value, suggests that a large portion of one of the main populations in the conflict is unwilling to accept the basic premise of a negotiated two-state settlement.
The article uses the finding to explain what the slogan 'From the River to the Sea' means to many of these respondents. It argues that the phrase is not a neutral call for Palestinian statehood but rather a demand for an Arab state across the entire territory between the Jordan River and the Mediterranean Sea, which would remove Israel as a Jewish state.
Because this is a single analytical essay, the data and interpretation come from one source. There are no separate studies or counterarguments presented here, so the numbers should be treated as one data point rather than a comprehensive measure of Palestinian opinion.