A response that is made to the claim that there is a slowing rate of significant technological innovation (and, one can infer, therefore scientific innovation) is that there is less ‘low-hanging fruit’ now than, say, 150 years ago. Therefore, it requires more investment to get a similar return, and in fact in many areas it seems to require much more effort to get even less return than people were getting 150 years ago
One problem with this response is that it assumes a static field of inquiry. Imagine an analogy in geographical exploration. Marginal exploration involves exploring parts of an already discovered continent. If one is only discovering within that continent, then it is easy to imagine how, in the beginning, explorers were able to make large discoveries relatively easily. It then would get more difficult to make new discoveries on the same continent on a similar scale, and at some point, it would become impossible.
Yet, what if genius opens up new fields of inquiry (i.e., the field is not static)? This would be analogous to figuring out how to find new continents (or beyond).
Consider those who were at the beginning of science – was their work easier than that of scientists now? Well, once you open up a new field for inquiry, there usually are low-hanging fruit, and the people first in an area are more likely to discover those. Yet, the people at the beginning of science were also those who were creating those fields.
So, if you are in a conventional field of, say, physics, it might be that the low-hanging fruit has been picked. Yet, it seems genius is involved in creating new fields of physics, hitherto unimagined. To some extent, we can say that genius simply is the ability to create new fields of inquiry – to create new conceptual frameworks that open up new ways of investigating.
The debate then seems to fall back on what reasons we have for believing that we have pretty much figured out everything, such that there isn’t much left to discover. This seems more an issue of judgment, and difficult to resolve.