‘Physics is the only real science. The rest are just stamp collecting.’ Spoken by Ernest Rutherford, Nobel Prize winner in Chemistry. This is a rather extreme view, but it is not uncommon among (primarily) natural scientists. It grabs on to an intuition many have, even in the academic philosophy of science community, that physics is the science, and that other disciplines – especially social sciences – are not. But let’s ask ourselves the question: is this true? Does physics have any special access to the truth that – let’s say – economics does not?
Let’s try to answer these questions. First of all, one has to separate the theoretical parts of physics and economics, from their empirical counterparts. Just like there is theoretical physics, there is ‘theoretical economics’ – although the latter is usually denoted by the more encompassing (and therefore misleading) term ‘economics’. Both theoretical fields try to construct logical or mathematical frameworks – possibly modelling the external world – and derive logical implications from accepting certain principles (the ‘laws’ of the framework). The prime difference is that economics takes individuals as its domain of analysis, while physics takes nature.
Now, let’s look at the empirical counterparts of physics and economics. Both experimental physicists and behavioural economists (a subset of the set ‘experimental economists’) do one thing and one thing only: set up hypotheses, gather data, compare the implications of the hypotheses with the data, and either confirm or refute the hypotheses based on their accordance with these implications. Hence the method applied in both experimental fields is the same. So now we have that the methods applied in both the theoretical and the experimental parts of physics and economics – and hence the whole of the two disciplines- are the same.
Now, given that the method applied is the same, how then could economics be any less scientific than physics? It might be true that physics has a longer history, and is – in that sense – more ‘mature’ than economics. But being more mature does not imply being more scientific. After all: many religions are more mature than physics: does that imply that many religions are more scientific than religion? Of course not.
It is then because there are laws in physics but not in economics? Well, it is true that physics has laws, such as the Law of Universal Gravitation, stating the acceleration of an object caused by the force of gravitation. But economics has laws too; the most well-known being the Law of Supply and Demand. One could say that the latter is not really a law, because it is only true ceteris paribus; that is, if all other conditions – besides the supply and demand of a particular good – remain constant. But isn’t this true for physics as well? In order for the Law of Universal Gravitation to hold, one should neglect such frictions as air resistance. So it appears that, whether it is in economics or physics, there are certain conditions one puts forward in order for laws to be experimentally accurate: neglecting air resistance in the case of physics, neglecting other factors – changes in cost of production, technological innovation etc. – in the case of economics. So the two fields do not seem to differ in that respect either.
Hence it is seems that the only difference between physics and economics, is its domain of study. But can the object of study really determine whether some field is more scientific than another? And if so, why would that be? It cannot be because physics’s object is more natural, because there is nothing unnatural about individuals; individuals are part of the world we live in, just like atomic particles, gravity and radioactivity.
Hence, given all of the above, there is does not seem to be any compelling argument for the claim that economics is less scientific than physics. Sorry mister Rutherford.
But what do you think?