when you put energy into a system you can never choose what kind of changes shall take place and what kind of result shall remain.  God has already decided those things.   all you can do, and that only within limits, is to regulate the amounts of the various changes.  this you do by <i>design</i>, which is the business of ensuring that at least you get the change you want along with all the others which you don't...<br>
 - david pye, nature and aesthetics of design