There is much in the hard sciences that we do not understand or may never know. So writes Prof. Doug Rawlings, former acting-dean of the Faculty of Science and for many years chair of the Department of Microbiology. The following is adapted from his farewell address given on 27 November 2015 – a light-hearted, tongue-in-cheek contemplation on knowledge and how it grows.

When speaking with colleagues in the general arts and humanities, it has been surprising to discover how encouraged many are to hear that knowledge in the hard sciences is not as cut-and-dried as they thought.

At an existential level, we wrestle with similar questions as we attempt to find answers. The question 'why do I exist; why does anything exist?' is something that concerns all of humanity and illustrates the point. The first part of the question is a search for purpose and meaning and has been asked for centuries. It falls within the professional domain of theologians and philosophers and is contained within the second part. The second part is a scientific matter and the current best answer is – we do not know!

It is called the fine-tuning problem, because so many constants have had to be fine-tuned for anything we experience to exist at all. Some accept it as divine providence, while it is in the nature of science to seek an explanation based on testable theory supported by evidence.

What can we learn from the physicists?

Half of the problems in this Faculty began with the acceptance of Einstein's theory of general relativity in 1915! This viewpoint is based on the following considerations. Physics is where the big science questions lie. Everything that we do and teach in the Faculty of Science is based on physics. Physics is considered to be at the apex with chemistry being a derivative of physics. Biology is said to reducible to physics and chemistry.  Even "pure mathematics" is thought, by some, to be based on properties of the universe. So we are all physicists or applied physicists of some sort.

Like every natural science student, I did physics in my first year as an undergraduate and it was the subject in which I obtained the highest marks. However, I decided not to continue with physics but rather to continue with applied physics which in my case was chemistry and microbiology.

The search after knowledge is like following a moving target

I think it is time that we who are applied physicists acknowledge some of the challenges our physics colleagues face and why we should be so grateful to them for teaching our students this important subject. Imagine what it is like to have to stand in front of a class and say – "we do not know what more than 80% of the stuff in the universe is, but let me tell you about the less than 20%"? As a physics lecturer, I would have found this rather uncomfortable, even a little embarrassing. To call it "stuff" sounds very unscientific and so we use terms like dark energy and dark matter.

But the truth is, nobody knows what it is.

What makes the situation worse is that when it comes to the less than 20%, we do not understand that either. Richard Feynman made this clear.  He was arguing that there are things that we know that we do not know and there are also possibly things that we do not know that we do not know. Quantum mechanics is like the latter for a chimpanzee. We know that we do not understand quantum mechanics, whereas a chimpanzee does not know that there is such a thing as quantum mechanics to be not understood.

* Click here to read the entire article, based on the farewell address.