I believe that the point being made by the person you're replying to isn't to avoid acting until future effects can be perfectly foreseen, as that milestone wil

I believe that the point being made by the person you're replying to isn't to avoid acting until future effects can be perfectly foreseen, as that milestone will generally never be reached. Rather, the future effects of an action should be evaluated to a level befitting the severity of the potential consequences. Put another way, if something can be trivially reversed and can't reasonably be predicted to result in any severe negative effects, then not much analysis is called for. On the other hand, if something can be reasonably expected to have a lasting impact, particularly a negative one, careful analysis prior to action is much more important. In cases where it's difficult even to articulate the approximate range of possible effects, a thorough analysis becomes extremely important.