The first line of defense against experimentation goes typically like the following: ``Doing an experiment would be incredibly expensive'' or ``For doing this right, I would need hundreds of subjects, I would be busy for years without being able to publish, and the cost would be enormous.''
To this, a hard-nosed scientist might say: ``So what?'' Instead of being paralyzed by cost considerations, he or she would first probe the importance of the research question. When convinced that a fundamental problem is being addressed, an experienced experimentalist would then go about planning an appropriate research program, actively look for affordable experimental techniques, and suggest intermediate steps with partial results along the way.
For a scientist, funding potential should not be the only or primary criterion for deciding what questions to ask. In the traditional sciences, there is a complex social process at work in which important questions crystallize. These become the foci of research, the breakthrough goals that open up new areas, and scientists actively search for economic ways to conduct the necessary experiments. For instance, the first experimental validation of General Relativity was tremendously expensive and barely showed the effect. The experiment was performed by Sir Issac Eddington in 1919. Eddington used a total solar eclipse to check Einstein's theory that gravity bends light when it passes near a massive star. At the time, this was a truly expensive experiment since it involved an expedition to Principe Island (West Africa) and the technology of photographic emulsions had to be pushed to its limits. However, it was important to test whether Einstein was correct or not.
Not many investigations are of a scope comparable to General Relativity, but there are many smaller, but still important questions to answer. How can such work be done economically? Since cost seems to be uppermost in everybody's mind, I will spend more space on this issue than on the others. My goal is to help the cost-conscious scientist or engineer overcome the cost barrier.
Experiments can indeed be expensive. But are all of them prohibitively expensive? I think not. There are meaningful experiments that fit the budget of small laboratories. There are also expensive experiments that are worth much more than their cost. And there is a wide spectrum in between.