Analyze the plausibility - if there can be any - of the contention that there might have been a certain justification for the September 11, 2001, terrorist attack on the U.S. Whatever your position, support it.
The plausibility of a contention that 9/11 might have justification depends entirely upon point of view. To devout Muslims in Islamic countries that filter and monitor cultural experience, there might indeed be plausibility for a contention of justification as they see America's "decadent" lifestyle and products infiltrate and harm their closed society. On the other hand, from the Western point of view of the average Western person, there can be no plausibility to a contention--nor even a consideration of a contention--of justification for 9/11's terrorist attacks. An expert in terrorism may have background and information tending to an objective point of view and therefore posit the absence or presence of plausibility on a sounder footing than personal experience, which is the limit of the two points of view mentioned above.
While it is impossible to answer this question directly -- as others point out, we don't know which readings have provided context for your classes -- we can draw from other sources.
For example, the lunatic fringe "9/11 Truther" movement believes that the attacks were predicated by the U.S. Government as a pretext for wars in the Middle East. In this model, the attacks were justified by governmental desire for war.
Doctors Quintan Wiktorowicz and John Kaltner show the explicit message in Al Qaeda's teachings about Jihad and the spread of Islam.
Wikipedia has a reasonably comprehensive article on possible justifications, or at least motives.
David Bukey wrote a good article on the religious motives for terrorism and suicide attacks for The Middle East Quarterly.
And, of course, a Google search will turn up every possible justification you could think of. The trick is finding sources you accept as credible and rejecting subjective views based on bias and ideology.
I think we need to be aware of the ways in which perception can alter the way that people view and think about things so radically and differently. Whilst for the majority of US citizens the way in which the US has intervened in the foreign affairs of other nations would be considered something good that it has done, for many outside of the US, and particularly in places such as South and Central America and the Middle East, it needs to be understood that US intervention in the affairs of other countries is an unwelcome and unpopular attempt to meddle and extend American imperialism.
There is a long history of Western "behavior" that would certainly justify the actions of Islam terrorists in their own minds, going back to the Crusades and probably even earlier. One of the problems I see is that we Americans have an unwillingness or inability to have any insight into the mindset of the "other." We have committed acts of aggression and violence that others could find unjustifiable, but our blinders prevent us from seeing that as well. Is terrorism ever okay? Certainly not. However, this assignment seems to me to be an excellent way of nurturing some critical thinking and some empathy.
The question doesn't seem to be what would have justified the terrorist attacks in our minds, but rather in the minds of those who carried them out. Assumptions that might justify a terrorist attack in the minds of the attackers could be that American policies contribute(d) to civilian deaths in their country. They may also not share the same aversion Americans have to taking civilian lives. They might assume that these types of attacks were the only way to strike out at the United States. They might even suggest that they had some sort of religious sanction for their actions. In short, if you're looking for some sort of abstract justification, you probably won't get one from most Americans. And there is not one under international law, which places a monopoly on the use of violence in the hands of states and international organizations like the UN. But surely the people who carried out the attacks felt justified in doing so.
I do not think that there is ever any justification for a terrorist attack. Even if the hijackers believed they were at war with us, there was no open combat and all of the people they killed were civilians. In war, it is acceptable to cause loss of life. However, bombing a group of civilians by hijacking airplanes does not even fall under the conventions of organized warfare. There can be no justification for this.
I believe that this topic reaches far beyond a simple discussion. I cannot fathom any assumptions made which would support the 9-11 attacks. Problem with answering this appropriately is that we (as discussion posters) do not know what readings have been completed "to date." While some of the readings may have had a well-supported thesis, without knowing the readings one can only stand on what they believe personally.
Therefore, I could not see any plausible assumptions/hypothesis which would justify the attacks.
Of course, we do not know what readings you have done and cannot, therefore, use hypotheses or assumptions from those readings.
One assumption that might be made to help explain such cases is the assumption that people's motivations are affected by their physical and economic circumstances. We often assume that people might become terrorists because they are poor or because they are oppressed. This is an assumption that might not be true as their true motivations may have nothing to do with their objective, measurable, socioeconomic statuses.