A good scientist knows what he knows and knows what he does not know. He has a good idea of his strengths and weaknesses and his areas of expertise and ignorance.
I know I know pterosaurs and theropods quite well, sauropods less well, ornithischians much less well and so on. I have a good handle on systematics and taxonomy and behaviour, but not on taphonomy or morphometrics. However, crucially, I also know people who are good at the things I’m not good at and are not good at the things I am good at. There are also people who are real specialists and can use a method or know a group better than almost anyone else alive, or generalists (which I’m certainly closer to) who can do a fair range of things quite well and link the other stuff together. Together we have breadth and depth.
This is important for two different reasons. Firstly it allows us to cover both a wide range of fields and get deep into them, without us all tripping over each other’s work. People can specialise or generalise and science will move forward as a result. More importantly though, it allows us to cross check and revise our collective work and have confidence in what we are doing across the whole of science, even, or perhaps particularly, when we have little or no understanding of that field individually.
I really do not know very much about astrophysics (big surprise). But I know a couple of people who do. I know the training they go through, I know the colleagues they have who check and review their work (peer review) and examine their ideas in the literature (through papers). I also know that those people are also cross-examined and checked by still other people and so on. It would be enormously time consuming, but I bet I can find a chain of co-authors and collaborators that links me to my collegiate astrophysicists. I have collaborators in geology and biology and some of them will have collaborators who are chemists and biochemists and physicists right up to guys working on star formation. At every point each person will have anywhere from a handful to dozens or even hundreds of collaborators, and dozens or hundreds or even thousands more who are reading and reviewing and replying to their papers. They have enough expertise to analyse each link in the chain, and perhaps one or two links either side of it, even if they can’t begin to handle either end.
Sure, there’s no-one out there (I suspect) who knows as much as I do about a couple of specimens I’ve worked on, but there are people who know nearly as much, and who know more about other close specimens, and know more about the methods I used to test them. This constant cross checking and evaluation means that we can have real confidence in our results and methods. I may not know how the stats package on my computer runs an analysis I want to use, but I do know that the mechanics have been written and tested by software engineers, I know the stats concepts have been produced by mathematicians and the methods have been verified by others. There are biologists with enough maths background to check the principles behind it and the appropriateness of the methods and the correctness of the results and so on. I know the taxonomy of the group at hand is right because enough taxonomists have checked the principles used to erect the species and specialists on the clade have looked at the anatomy and ecology and confirmed the species are distinct and so on. They may not know each other or even recognise each other’s work (I suspect you could really confuse a mathematician with a graptolite and some whale baleen), but it all fits together.
In this sense then, scientists are not so much a group of individuals as a cohesive whole. There are, obviously, errors made (occasionally profound ones) but this colossal network of research ideas and analysis does produce a singular, and generally very reliable, whole. I may not understand astrophysics, but I recognise and trust the methods used to generate the data, the analyses and the people behind it. So can you.