Of course, the role of intelligent agents in guiding evolution is not exactly new. Sexual selection and The Baldwin Effect provide clear mechanisms where the choices of intelligent agents can go on to influence the course of evolution.
However, intelligent design and engineering are new evolutionary forces. They are also relatively complex and difficult to understand.
There have been some attempts to break intelligent agents down into more comprehensible pieces - and to model intelligence as a Darwinian process. When that can be done, variation will no doubt be found to arise by a range of simpler processes - which will ultimately arise from basic physical processes. However, these kinds of model are not yet finished - and they don't yet work. Today there isn't much of an alternative to modelling choices made by intelligent agents at a high level - using primitives such as "agent" and "preferences".
Basically, this means that we need a science of intelligent design - to help us understand the evolution of culture. Of course, in some respects we already have this - science studies various aspects of engineers and engineering. However, there are a number of significant areas that remain not so well studied.
Designed entities have somewhat different properties from designoid ones. They show different kinds of evolutionary mistakes. Designers have better refactoring capabilities than simpler forms of evolution. They also typically apply different fitness criteria to their productions. However, designers have limited access to molecular nanotechnology - and they don't yet have access to much of nature's parallelism.
As a result of these kinds of factors, mobile phones and cats are very different kinds of entity. Also, the evolution of the mobile phone is systematically different from the evolution of the cat - though both exhibit the key evolutionary hallmark of gradualism.
So far, there hasn't been much scientific study of these kinds of differences. We haven't had a proper science of cultural evolution - so comparing cats with mobile phones has probably seemed pointless to most people. However, now, things are different. We now understand the importance of intelligent design to cultural evolution - and so next we need to study it.
I have long debated how to present the issue of intelligent design to the community of evolutionary biologists - without provoking a memetic immune reaction and immediate rejection. Intelligent design is commonly - but falsely - assumed to be a realm of boundless crackpottery.
One possibility is to call it something else. Engineering design is the most obvious alternative. However, I think that intelligent design is a better name. I'm not the only one to use it - for example, here is Daniel Dennett:
We are the first intelligent designers in the tree of life.
Here is Richard Dawkins, speaking at the Reason Rally on March 24th 2012:
Now at last, finally, after four billion years of evolution, we have the opportunity to bring some intelligent design into the world. We need intelligent design. We need it to intelligently design our morals, our ethics, our politics, our society. We need to intelligently design the way we run our lives.
I don't think that common use of the term "intelligent design" as shorthand for the idea of intelligent design of nature by god should be too much of an issue. That is indeed a type of intelligent design - or at least it would be if it actually existed. Yes, there's the issue of search term pollution. However, I think that it is more important to use the right words, than to bother too much about any squatters who are currently using them.
I think it's also useful to be clear about what Intelligent Design is not. It's not this:
Intelligent Design is simply the science of design detection — how to recognize patterns arranged by an intelligent cause for a purpose.
That's part of the subject area - but there's more to it than that. Science is about building models and making predictions; it's not just about recognition and classification.
intelligent design may not have been an important force in the past, but it looks set to be an extremely important force in the future. We should start to study it properly now.