Start with an account that a historian would give, one that is as complete as possible. Next show how these factors supervene on the mental activities of the individuals involved with declaring and waging the war.

The concept works the same way as usual - the brick thrown causes the broken window - not the other way round, except indirectly - break my window and I might throw a brick at you, but not the throw that broke the window. But best not pretend that history is a science; there are no repeatable experiments, as initial conditions cannot be controlled.

But my impression is that the general feeling about WW1. is that economic and political conditions made war inevitable 'sooner or later', and the assassination was more so a pretext or perhaps a trigger than a cause.

How can we say that the assassination of Franz Ferdinand was a factor in causing WW1?

Because it was the immediate point on wich the war was built on. It was because of the assassination the Austro-Hungarian's sent a letter with demands that is not meant threatened war.

Also be more specific assassination of Franz Ferdinand was only the Immediate cause, it was not the only reason the war happened (Most people do leave "immediate" out when telling the story so I can understand if you didn't get that).

How would a concept like causality work... — curiousnewbie

Cause is immensely difficult. Think that through and you'll have not-so-much trouble in understanding accounts of the cause(s) of WWI, or anything else for that matter. Until you do, you belong to whoever tells you anything - because you won't really understand it.

But best not pretend that history is a science; there are no repeatable experiments, as initial conditions cannot be controlled. — unenlightened

Good point.

What is history other than a historical account. The historical account is a means of remembering the past. But, memory is not history, and whenever memory is communicated, it is simply a historical account.

Historical accounts are indeed capable of accounting for causation, but not in any scientific way.

How can we say that the assassination of Franz Ferdinand was a factor in causing WW1? — curiousnewbie

Because it kick-started the conflicts that led to WW1. If it didn't happen, we might be living in a world with a lot of imperial states and we might even not have computers as we do today. Much of today's technology comes from innovation pushed by two world wars. The conflicts before WW1 might have led up to a smaller scale war, diplomatic tensions etc. and other types of outcomes than how history turned out to be.

Causality is like domino bricks falling onto each other; just scale them up to more complex models.

How would a concept like causality work when trying to explain mass scale events. How can we say that the assassination of Franz Ferdinand was a factor in causing WW1? — curiousnewbie

I'm not exactly sure what you are asking here. A declaration of war is an intentional act for which reasons are given. The reasons would be the cause of the declaration of war.
Does the Austrian-Hungarian declaration of war mention the reasons it was declaring war? If so, then why would anyone argue that those aren't the causes of the declaration of war? If you give a reason as to some behavior of yours, are we suppose to reject those reasons as causes of your behavior?

But best not pretend that history is a science; there are no repeatable experiments, as initial conditions cannot be controlled. — unenlightened

History would be the theory and archaeology the science that uses evidence to propose those theories. Criminal investigators use the evidence at the crime scene to create a theory of what happened.

But my impression is that the general feeling about WW1. is that economic and political conditions made war inevitable 'sooner or later', and the assassination was more so a pretext or perhaps a trigger than a cause. — unenlightened

Sure, there were pre-existing tensions between the countries, and that might have led to war at some point, but why did war break out when it did, instead of some other date?

What is the difference between a "trigger" and a "cause"?