Does philosophy have anything interesting to say about the problem of terrorism?

Yes, please go to the free, online Stanford Encyclopedia of Philosophy and see the entry: TERRORISM. There is a good survey of the terms, concepts and work that philosophers have contributed to. Because that will give you a full overview and guide plus recommended reading, I think it would be redundant of me to offer a great deal of material here. But I offer just a few thoughts as a preface to your looking at the Stanford entry:

Philosophers have done a great deal of work on justice, law, and the use of force. You will find a great deal of this in simply pursuing the domains of political philosophy and philosophy of law, but also in the context of Just War Theory.

Contemporary acts of terror / terrorism are not unprecedented historically, but as you will see in the Stanford entry, there are vexing issues in addressing terrorism within and without state sponsorship, and great differences between ostensible justifications of terrorism (e.g. nationalism, utilitarian rationale, theological warrants) and the recourse to eliminating or minimizing terrorism (e.g. how to balance individual liberty and civic safety).

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