I decided to start this because it seems that terrorists only seem to want to attack western civilisation for absolutely no reason. Does anyone know why they actually want to attack people, and what they hope to achieve?

... you do know there are western terrorists too don't you?

they bomb/attack for an ideal, usually one not many people accept or understand.

They attack, I imagine, because they think that sacrificing thierselves for thier beliefs will give them honor ect. It's an alright belief, our soldiers think the same way. However, it's not nearly as noble in real life when they're attacking civilians and not military targets.

isn't this question a bit like saying "what do americans want?"
You will probably get as many different answers as you can find people willing to answer it.

Usually, what terrorists want is what they ask for. There are some terrorist groups who want things like anarchy, or communism (such as the red brigade) but you tend to find that MOST terrorist groups have arisen where people feel opressed.

This often leads to the situation where some some people see them as terrorists, others as freedom fighters. The most blatant example of this can be seen in Nelson Mandela and the ANC... who were once regarded as terrorists, then became leaders of governments.

The IRA wanted a united ireland.
The protestant paramilitaries wanted to stay in the UK.
ETA want their area of spain to be a seperate country.
Timothy McVey wanted "freedom" from the US and UN governments.
"Terrorists" in east timor want freedom from an oppressive government.
"Terrorists" in south america often want deocratic or socialist governments, freedom from US interference and an ending to oppression of racial minorities.
Palestinian Terrorists want their own state, and their land back from israel.
Kurdish Terrorists wanted freedom from oppression by saddam and turkey
Afgan terrorists wanted freedom from the USSR
Indian terrorists wanted freedom from british rule
Algerian terrorists wanted freedom from french rule
Chechen terrorists want freedom from russia

While terrorism is never a good thing, it doesn't USUALLY just pop up cos people think "hey, lets kill lots of people". There are usually deep seated problems or feelings of oppression (although not always correct) that lead to deep seated hatreds and a feeling that there is nothing left to loose.
And while "targeting civilians" is never a good thing, most often the terrorist/freedom fighter will be dramatically underpowered compared to their (real or imagined) oppressor and will feel that it is their only way to strike back.
There was an interview with a palestinian i saw where he basically said "you think we like blowing ourselves up? if we had tanks and planes we would fight the army with tanks and planes, they have tanks and planes... we have home made explosives."

I guess what nost specific attacks want is to
(a) Cause fear and thus make people exert pressure on their governments to stop watever the terrorists want stopped.
(b) Bring worldwide attention to their cause.

"Fear and Awe" tactics if you like. You could argue on one hand that terrorism can be an efficient way of making your point, as the fear it creates is often way out of proportion to the deaths it causes. Kill 100 US soldiers in iraq and no-one notices. Chop off 1 head and it is on the news around the world.
On the other hand, as far as i can tell, terrorism almost always HARDENS opinion AGAINST what it is the terrorists want. EG: The NI peace process could only really start once they stopped the attacks. Israel hardens its stance after each attack.

If you are specifically talking about Al Quaida, i'd say that they want
(a) The downfall of the Saudi Government which they see as a corrupt monarchy, a pawn of the US (although it could be argued it is the other way round). (NB. AQ was basically formed in response to US troops stationed in SA to protect the regime)

(b) The removal of secular islamic governments and creation of religious ones.
(a) The US to stop unfairly supporting certain regimes and undermining others, while (as they see it) the common muslim on the street gets stuck in the middle.
(c) An islamic world (unlikely)
(d) the downfall of saddam (looks like the US helped them on that one)

But i might be wrong. IMHO Al Quaida is mostly a smokescreen created by the US as a target. It isn't running a vast network of other groups or anything. There are basically loads of mostly independent groups who all have their own causes, but who have occasional contact with each other to pass info/weapons/whatever. The only thing most of them have in common is that they hate the US. But then again. who doesn't.
*kidding* :D

The problem is that there are hundreds of little things that the US does that keep adding to the general impression people have of it and increasing levels of hatred. And every helicopter attack in the west bank, or in iraq that leaves someone dead also leaves a whole load of bereived relatives who are much more likely to aid, abet, support or become terrorists in the future.

Try watching the peacemaker or the seige for a dumb hollywood look at how people become terrorists, and the dangers of giving them exactly what they want (us changing ou lives, giving up our freedoms and persecuting those who are different).

From Mort-hog in the islamic dilema post...
When I was in Egypt, I found it very interesting that the Egyptian newspapers never used the word "terrorist". They were not particularly anti-American either, but they always made references to the groups by name. I too think the Bushism "terrorist" is now utterly meaningless. I mean, Al Queda and the Al Aqsa Martyr's Brigade both make use of martyrdom operations, but other than that they are totally unrelated and have nothing in common. H.A.M.A.S, Islamic Jihad and Hezbollah are all labelled "terrorist" even though they are very different and very specific organisations (Hezbollah is totally the coolest name of them all, might I add). I also think it's interesting how the Kurdistan Worker's Party, Aum Shinrikyo, KKK, Christain Patriot movement, and the Tamil Tigers (who make up the vast majority of all suicide bombings in the world) are rarely referred to as "terrorists", if at all. It certainly makes the word "terrorist" seem to refer to Muslim groups only. Also it is interesting how the US state department has a list of "Designated Foreign Terrorist Organizations" but there is no formal list of domestic 'terrorist' groups even though Americans are responsible for three quarters of all incidents classified as "terrorism" by the FBI. When talking about such things, I always try to be as specific as possible. I try to avoid using the word "terrorist" if I can.
hope he doesn't mind me posting it here too...

What do terrorists want? Well, as the Verfassungsshьtz found out by dealing with RAF, terrorists are usually the first to tell you what they want.

Ordinary politicians lie, cheat, and steal, but - partially because of their extreme methods - terrorists have to be brutally honest, because they need to justify their actions to their supporters, and they usually don't care how their detractors view them.