With Secretary of State Condoleezza Rice visiting Israel this week and President George W. Bush expected next week, talks about peace between Israel and the Palestinians are on the agenda yet again.

This elusive peace is widely proclaimed as both essential and achievable. But while the former is true and desirable, the latter is a widespread misperception. The solution to the conflict exists and is well known, but it cannot be implemented in the foreseeable future.

Many policymakers and commentators believe a solution to the Palestinian-Israeli problem is possible for several reasons: First, rational people believe in rational solutions; second, the conflict is deemed "too important" not to have some resolution; third, the outlines of such a rational solution have been drawn time and again, so that the mere existence of a solution encourages belief in its implementation.

Over the past 12 years, four plans have offered a similar formula based on the establishment of two states. Indeed, the declaration issued at the end of the recent Annapolis conference builds on this logic.

So why should a rational solution have little hope of being achieved? Because there are serious disincentives to making peace that have to do with demographics, the intensity of violence and economics.

Moreover, feedback mechanisms in operation reinforce the disincentives. Consider demographics: The median age of Palestinians is 17 years. Compared to a median age of about 37 years in the United States and 30 in Israel, the Palestinians are a very young nation.

A staggering 85 percent of the Palestinian population is under 40, and so was born under Israeli occupation, which began in June 1967. More than 40 percent of the Palestinians experienced the second intifada, or uprising, against Israel as infants or children. These facts mean that the majority of the population has experienced Israel only as an occupying force, within an increasingly violent environment.

More than 4,300 Palestinians have been killed in the past decade alone. The number of injured or traumatized Palestinians is in the tens of thousands. Given that it is very difficult to alter one's perception of the world formed in childhood, the probability that Palestinians will become more favorable toward Israelis is really nonexistent.

In an illuminating interview in The New York Times Magazine last year with a Hamas activist, Steven Erlanger quoted the man as saying, "I think this generation will be the liberation generation. If in the past, 1 percent of the people went into resistance, from this generation, 20 percent or more will do it. . . This generation will be our liberation army."

Potent feedback mechanisms reinforce these disincentives for peace. One has to do with the economic situation. Since 1999 the Palestinian economy has shrunk by about a third in per capita terms. The rate of unemployment has risen from 14 percent to 22 percent in the period 2000-2005, with recent numbers indicating high double-digit figures in Gaza.

The percentage of people below the poverty line has increased from 20 percent in the second half of the 1990s to over 40 percent, with approximately 15 percent classified as living in deep poverty.

This situation is a breeding ground for those who wish to buy influence through economic aid. One such group is Hamas, which built its political success on charity. Others include Iran and Al Qaeda.

Indeed, an adviser to the Hamas prime minister in Gaza, Ismail Haniyeh, proclaimed in January 2007 that Hamas had received pledges of about a billion dollars from the Islamic world, in particular from Iran. A vicious cycle comes into play: Once Hamas, Iran or Al Qaeda institutions flourish, aid coming from other sources is reduced, further strengthening the value of the radicals' aid.

A second feedback mechanism involves radical Islam. As conditions of daily life become increasingly difficult, the Palestinians become easy prey. Islamic groups provide both material aid and spiritual comfort. The more rigid the doctrine, the more it eases the psychological difficulties of living in a violent, poor, and hopeless environment. The chaotic, desperate reality is explained and framed by a narrative that defines good and evil while promising justice.

Moreover, the Islamic movements have a broader agenda that bears upon their struggle with the West. Such groups have no real interest in a solution to the Palestinian-Israeli conflict, as it may render their role redundant. They want to use the Palestinian situation as a springboard to wider activities.

Israeli policy, often driven by powerful minority groups, has contributed its share. There is a process of gradual absorption of Palestinian territories, with more than 160 Israeli settlements in the West Bank. Over the past decade, the number of settlers has increased from about 150,000 to more than 250,000.

Summing up, Palestinians grow up under occupation, experience violence as a childhood fact of life, face dismal living conditions, are aided by radical Islamists, and meet with hostile and aggressive Israeli incursions into their territory.

Looking ahead, the Palestinians believe there are processes working in their favor.

First, they see that Israel has ceded territory: in Sinai in the 1980s, in Lebanon in May 2000 and in Gaza in Ariel Sharon's August 2005 disengagement. Many interpret these pullouts as results, respectively, of the 1973 War, of the Hezbollah attacks in Lebanon and of the Hamas terror attacks from Gaza. Second, the July-August 2006 war in Lebanon exposed Israeli vulnerabilities. Third, Palestinians are well informed about the workings of Israeli society and spot weaknesses within Israel and the increasing fragmentation of its society.

Finally, if current demographic trends continue, there will soon be a clear majority of Arabs in the area between the Mediterranean Sea and the Jordan River.

In such a case the two-state solution may cease being feasible, since the presence of Arabs in Israel and Jewish settlers in the West Bank will make the drawing of clear demarcation lines impossible.

Peace is desirable because of the need to end the misery of so many terrorized, hurt and oppressed by this conflict. But strong fundamental forces are at play against this peace.

These negative forces have strengthened over the decades of conflict and are very likely to persist. For the foreseeable future, they may also triumph.