After the 2015 Charlie Hedbo murders in France, the discussion of group responsibility heated up. Some contend that all Muslims were responsible for the actions the killers. Most people did not claim that all Muslims supported the killings, but there was a tendency to put a special burden of responsibility upon Muslims as a group. Some people did claim that the murders were evidence that Islam itself is radical and violent. This sort of “reasoning” is, obviously enough, the same sort used to condemn all Christians or Republicans based on the actions of a few.
To infer an entire group has a certain characteristic (such as being violent or prone to terrorism) based on the actions of a few involves committing the fallacy of hasty generalization. This “reasoning” also often includes the fallacy of suppressed evidence in that evidence contrary to the claim is ignored. For example, to condemn Islam as violent based on the actions of terrorists would be to ignore the fact that most Muslims are as peaceful as people of other faiths, such as Christians and Jews.
It might be objected that a group can be held accountable for the misdeeds of its members even when those misdeeds are committed by a few and even when these misdeeds are supposed to not match the beliefs of the group. For example, if I were to engage in sexual harassment while on the job, Florida A&M University can be held accountable for my actions. Thus, it could be argued, all Muslims are accountable for the killings in France and these killings provide just more evidence that Islam itself is a violent and murderous religion.
In reply, Islam (like Christianity) is not a monolithic faith with a single hierarchy over all Muslims. After all, there are diverse sects of Islam and many Muslim hierarchies. For example, the Muslims of Saudi Arabia do not fall under the hierarchy of the Muslims of Iran.
As such, treating all of Islam as an organization with a chain of command and a chain of responsibility that extends throughout the entire faith would be absurd. To use an analogy, sports fans sometimes go on violent rampages after events. While the actions of violent fans should be condemned, the peaceful fans are not accountable for those actions. After all, while the fans are connected by their being fans of a specific team this is not enough to create accountability. As such, to condemn all of Islam based on what happened in France would be both unfair and unreasonable.
This, of course, raises the question of the extent to which even an organized group is accountable for its members. One intuitive guide is that the accountability of the group is proportional to the authority the group has over the individuals. For example, while I am a philosopher and belong to the American Philosophical Association, other philosophers have no authority over me. As such, they have no accountability for my actions. In contrast, my university has authority over my work life as a professional philosopher and hence can be held accountable should I, for example, sexually harass a student or co-worker.
The same principle should be applied to Islam (and any faith). Being a Muslim is analogous to being a philosopher in that there is a recognizable group. As with being a philosopher, merely being a Muslim does not make a person accountable for all other Muslims any more than being a Christian makes one accountable for the actions of every other Christian across time and space.
But just as I am employed by a university, a Muslim can belong to an analogous organization, such as a mosque or ISIS. To the degree that the group has authority over the individual, the group is accountable. So, if the killers in France were acting as members of ISIS or Al-Qaeda, then the group would be accountable. However, while groups like ISIS and Al-Qaeda might delude themselves into thinking they have legitimate authority over all Muslims, they obviously do not. After all, they are opposed by most Muslims.
So, with a religion as vast and varied as Islam, it cannot be reasonably be claimed that there is a central earthly authority over its members and this would serve to limit the collective responsibility of the faith. Naturally, the same would apply to other groups with a similar lack of overall authority, such as Christians, conservatives, liberals, Buddhists, Jews, philosophers, runners, and satirists.