Reactive and proactive as relative terms

This is one of the most famous visual paradoxes, in this picture one can see a young girl or and old woman, some people see only one of them, with some concentration one see both.   This is a kind of relative view, in event processing there are some relative terms, I have written a while ago about the fact that the terms raw and derived events are relative,  a derived event in one sub-system can be raw event of another sub-system.. 
There are other cases of relative views (an entity may be both consumer and producer, for instance).  


I have reminded on relativism while reading an article about the keynote talk of Jeff Shulman (Gartner's manager of the application integration and web services analysts team).  Shulman is talking about cloud, mobile and CEP as the leading trends for application development and integration.   
As a remark to Shulman's keynote, the article bring an interesting response of  Chris Dressler, VP Technology in Cablevision,  he sees a  CEP can be used to find and correct issues before the end user has the need to make a complaining call.
This is an interesting example,  from the service provider's point of view (cable TV company in this case), this is a reactive application, tracking events that already happened and react to them, from the home consumer point of view this might be proactive, since the consumer may not yet felt the impact of the problem, so from the consumer point of view, this is elimination of problem that has not really happened.    More on this distinction - later. 

Relativity and Event-oriented thinking

You may be familiar with the magnificent masterpiece of Escher called "Relativity". We see relativity everywhere -- on Saturday I've called home from my hotel in Burlington (since then I've moved south, and now I am in Hawthorne, NY) and told my daughter that I am sitting in the hotel waiting for the snow to end, in order to get out, and she said -- "how lucky you are to see snow", I have not felt lucky to see the snow, in fact, it kind of disrupted some pans I had, but in the world of a person that lives in Haifa, snow is a rare thing that occurs once every 20 years for a short time, so it is an attraction. At some point in my past I have been teaching a basic AI course, and the teaching assistant has taught the students Lisp. I have looked at the end of the semester on Lisp code produced by students - some got it right and wrote pure recursive program, and some wrote code that looked like Fortran thinking in Lisp.

The same relativity exist when dealing with event-based applications. Some people understand how to construct such applications, while other people think in other paradigms like request-respond, and are trying to do some blend here. It is perfectly OK to do an hybrid approach, but this should be a result of careful design, and not by chance. Bottom line - we need a methodology for constructing event-based applications and tools to support it - this will somewhat different kind of thinking... more about this topic - later,