Risky metaphors
Deep knowledge and understanding is not easy, but associating concepts with images if only symbolic can be a powerful way of learning, boosting confidence in the concepts and allowing elaboration and increased understanding. In various fields, such collective imagery is a cultural inheritance, facilitating the transmission of ideas and giving a valuable vision of reality.
However, such iconography becomes more and more difficult and risky for fundamental physics. There are no conventional images for microsystems and moreover we have no authority to invent them. In addition, these representations are usually not self-explanatory but require their own interpretation using other metaphors. Consider the representation of the "constituent" quarks of a proton as small "coloured" spheres, suggesting an image of "particles" building a "particle" all the words in quotes are dubious metaphors.
Human imagination and scientific creativity work by evoking sensory impressions. For the microworld, our intuition rests on formulating the visual imagery of the underlying mathematical structure of a physical theory. Bubble chamber pictures can be held up as visualizations of particle interactions, but because of the complexity of the experimental setup, such pictures are many layers removed from the "raw" mechanisms of particle collisions. The pictures show the result of particles interacting, but not how they interact.
On the other hand, Feynman diagrams provide a valuable glimpse of an otherwise highly intangible world. However, a lot of work is needed to formulate such enlightenment: but we can use them as a starting point for metaphors which are more correct than those based on classical concepts.
The main problem with metaphors, useful though they are, is that they do not give any clear indication of their areas of applicability. Using them out of context can lead to misunderstandings. They may be effective tools for informed scientists, but a straw in the wind otherwise. Metaphors can help bridge an intellectual gap, but there is no substitute for understanding. Ultimately we have to exploit logic, not facile pictures.
The role of science is to explain, to communicate. There are communication difficulties, but the more conspicuous they are, the more effort should go into overcoming them.
Another paradox is that the popularization of science is not always popular among scientists. Many see it as a lowering of standards, a loss of rigour. Whilst remembering Einstein's advice that "everything should be made as simple as possible but not simpler", scientists must nevertheless be tolerant of efforts to communicate difficult ideas and help to bridge the gap between scientists and the public.
Happily, there is now an increased interest in such "outreach" activities in particle physics by individuals and institutions. In France, where most scientists are civil servants, this duty has recently been written into their contracts of employment. In the UK, research groups are allowed to devote up to 1% of their research resources in education and communication activities.
In the USA, major experiments are engaged in a broad spectrum of outreach initiatives, and in particular the ATLAS and CMS groups for CERN's LHC collider are highly productive. In Europe, an overall "European Particle Physics Outreach Group" has recently been set up, coordinated at CERN by Frank Close.
For all these initiatives, the goal is to convey emotion the thrill and excitement of frontier research and discovery. We are fortunate that our business is to investigate some of the most interesting and fundamental issues in the history of science and of civilization itself. What better subject matter could there be?