Engineering Knowledge Half Life: When is it okay to NOT know the detail?

To some extent I question the statement's accuracy given that it was posted on a website that was building a case for its training services. But continued web searching revealed broad support for the knowledge half life concept with figures ranging from two to eight years. So, while we could all argue about the exact timeframe, the reality is that our knowledge as engineers is decreasing over time and unless we do something about it, so too will our value. It may seem that the best defence is to replenish our knowledge with newer, more up to date information. As long as we can keep up with the latest chips and technologies then we are assured of maintaining our value and relevance into the future. But is that all we need to do, or is there another option? I was recently part of a web panel that discussed the impact that high level design tools are having on the roles of domain specialists and detailed designers. The point of contention was that high level design tools are increasing the influence of domain specialists and taking the jobs of detailed designers. Part of that debate revolved around the idea that high level design tools take care of low level implementation issues and free the domain specialist from needing to know the underlying detail. In fact, in the extreme case, the designer may not even know anything about the underlying detail. Which brings me to my point; when is it okay to not know the detail? The biggest impediment to change is knowledge. By being loyal to knowledge beyond its use by date, we limit our ability to detect disruptive technologies and to capitalise on their benefits. Maybe it's time to let go of the perception that our tightly held knowledge holds some sort of intrinsic value. As detail oriented people, we engineers take a certain amount of pride in our ability to use and manage complex information as a regular part of our daily work. It is so ingrained that it almost feels like cheating if we build something without knowing the inner workings of the system. But if we consider the fact that our knowledge has an ever decreasing lifespan, there will be many times when it is simply not worth taking the time to acquire knowledge that is so transitory in value. And as foreign as it may feel as an engineer, maybe we need to become more comfortable with not knowing the detail.