All science is either physics or stamp collecting

 What is science? In one simple sentence, science is the study of nature. However, different sciences like: astronomy, chemistry, biology, geology, etc. have different approaches to do so. Thus, not all sciences are equal.

The quote 'All science is either physics or stamp collecting' by New Zealand physicist Ernest Rutherford perfectly reflects that inequality. According to him, physics is the king of science because it is universal.

But why exactly did Rutherford think in that manner? Despite himself being the recipient of Nobel Prize in chemistry, what made him consider physics the most noble of sciences?

The answer lies in stamp collecting - a hobby in which people collect and classify stamps as objects of interest or value.

Stamps are available in many varieties - big and small, square and round, stamps with famous human faces, stamps with animals and birds, stamps commemorating anniversaries, etc.

 Rutherford's stamp 

Similarly, some sciences such as zoology or botany for example are mostly concerned with collection and classification of species - animals and plants, respectively.

Although this would be dumbing down those sciences but that is more or less the purpose, isn't it? In other words, those sciences are not fundamental sciences and their scope is limited only to Earth.

Physics, according to Rutherford, is the only science that has an elaborate structure consisting of observation, experiment and mathematics. It truly is the universal embodiment of the scientific method.

By this definition, the science which is closest to physics is astronomy. Like, you observe and measure the effects of a black hole on its surroundings, for instance, with the help of telescope and mathematics.

Chemistry comes next. As chemistries can be different in different places - even though the laws of physics that govern those chemistries remain the same.

Likewise, sciences like computer science and psychology are not universal. Furthermore, they are heavily dependent on mathematics and observation, respectively.

All the sciences, however, must ultimately be experimental because that is how they progress. That is how the hypotheses are tested and verified and accepted.

Finally, it is important to mention that the statement all science is either physics or stamp collecting had more truth to it in Rutherford’s day than today.

As you know, for example: With Darwin's theory of evolution, biological sciences have too become observational rather than just being classification sciences.

So, over time, sciences evolve and become more and more physics-like. To maintain Rutherford's point though, physics will always be the only universal science.