Provisional truth is good enough

‘He came rushing into the university cafeteria, with his wild Einsteinian hair, shouting and punching the air excitedly: ‘Yes! They are there! They really are there! They have proved that quarks exist!’ ”

So does the Academy of Science of South Africa’s (ASSAf) distinguished visiting scholar for the year, Professor Bengt Gustafsson, remember an emblematic moment in his formation as an astrophysicist, back in the mid-1960s.

The moment was decisive for him, he explains, because it showed the necessary interpenetration of theory, observation and experiment in the progress of scientific understanding, a continuing process he refers to as the gradual shifting and development of “provisional truth”.

Back to 1964, when many scientists doubted whether quarks existed – although two had separately posited the theoretically necessary existence of quarks as elementary particles in the constitution of all physical matter.

Perhaps, the sceptics charged, the idea of “the quark” merely worked to fill, apparently, a gap in then current knowledge, but that in reality the gap pointed to the need for a better theoretical explanation, one that would be securely grounded in observable reality.

Four years later, results from 1968 experiments at the Stanford Linear Accelerator in the United States at last gave the solid ground of actual scientific observation to confirm the theoretical speculation, and hence the Swedish academic’s triumphant air-punching. This moment of triumph was one in which speculative theory proved to be true, and the concept turned out to have correctly anticipated what was later confirmed by empirical observation.

Origins of the universe
In his lecture to ASSAf on February 5 at the University of Cape Town, Gustafsson’s second example was the confirmation of the Big Bang theory concerning the origins of the universe. For a long time, many scientists rejected the theory, including the great British physicist Fred Hoyle, who, like Gustafsson, did much to bring scientific discovery and speculation into broader public forums.

Ironically enough, it was a deliberately pejorative remark of Hoyle’s that gave the name to the new theory, which he referred to as “the hypothesis that all the matter in the universe was created in one big bang at a particular time in the remote past”.

Here, the first experimental confirmation of the Big Bang theory, and contra critics such as Hoyle, came accidentally with the discovery of cosmic microwave background radiation in 1964 – and was further enhanced in 1992 by evidence that the Cosmic Background Explorer satellite had been deliberately programmed to gather. These measurements revealed that, as the theory had suggested, the Big Bang released some 99.97% of the radiant energy of the universe.

In each of these cases – and as a general pattern in scientific discovery – what is crucial, Gustafsson argued, are the ways in which consensus is generated from a range of theoretical speculations, with the people involved often taking off from very different philosophical positions, but coming together as decisive experiments show the way.

Central to this whole process, he suggested, is the general pragmatism that animates scientists, their guiding sense that “naive realism works”. “Provisional truth is good enough” in the continually self-adjusting process of scientific progress, he insisted. “We can do good science without understanding everything,” he emphasised.

Gustafsson’s career in astrophysics came second to his first interest, which was in architecture. But his father’s move to the Royal Technical Institute in Stockholm, where architecture was housed, prompted his own move to another university and another choice of degree. There, he began with physics, but continued his lifelong interest in astronomy, which had begun as a child when he carefully sought out the moon’s craters and identified stars with a simple telescope, and, as a high school pupil, he was already giving public talks on astronomy.

Major contributions
For his doctoral research, he studied stellar physics and, as the former director of the South African Observatory, Patricia Whitelock, put it: “Gustafsson has made major contributions to our understanding of the atmospheres of stars, including that of the sun. These help us envisage how our galaxy and in particular our own solar system began. For the future his insight is leading to new measurements that will tell us if more distant stars could have planets like the Earth.”

Despite Gustafsson’s success in his research specialisation, he admitted he has often strayed from its inevitably narrow focus. “I belong with those who think we only have one life, and that we should try and expose ourselves to the most interesting things we can.

“There is a risk involved in the concentration needed to become a specialist. I have published a lot of papers over the years, and have been influential in my field, but I did make some choices to also move away from that. I spent some years in a project looking at science and religion; others looking at science and society; and also spent time working with government on research policy and so on. I also accepted guest lectureships for the interest of the location rather than that of the science. Maybe I could have been a better scientist if I hadn’t done all this … but I’m not sure.”

Research scientists, he said, can “get to develop a love-hate relationship with” what they do. “Scientists can reach a saturation point, and get bored with what they do, and have to be extremely disciplined and work very hard to get through that. I solved this saturation problem simply by doing something else for a while, and then going back, refreshed, to my research.

“That’s also why I like giving public and popular lectures on science and astronomy. In doing so, I get back to the joy I felt as a child, exploring the skies with a simple telescope. By doing other things, I come back stronger.”

We discussed the success of South Africa’s bid, and its excitement, to play a major role in the Square Kilometre Array project. I remarked on the ways in which, during the conference that celebrated the successful bid, Science and Technology Minister Naledi Pandor spoke entirely of the instrumental applications that might arise from the project, but didn’t mention that, of all academic disciplines, astronomy is perhaps the most blatant example of curiosity-driven research.

A political question
I asked him how he felt about the tensions, about supporting scholarship, that derive from curiosity-driven versus applied research. “It’s a political question,” he replied. “I have worked with politicians, and served as an adviser. The important thing is to separate the ambition that animates scientists from the ambitions that politicians have.

“For us scientists, free work is our thing, it is our virtue. You have to work hard, but you are free to choose what work you want to do, and so you are motivated – and that is the key thing. But, when it comes to the politicians and the taxpayer, this cannot be the justification.

“There are many urgent needs, and you have to accept that, as a scientist, even if you find this or that topic wonderfully interesting, it’s not automatic that the public will go for funding it. I have lots of good friends in opera and dance, for example: except for the real stars in those disciplines, they are much poorer than me. Why should the state spend so much money on me?

“I think it is necessary for scientists to see what they are good for, from the public point of view, and say, ‘Yes, we are doing those things,’ and to say to ourselves that we are also satisfying our curiosity.”

Astronomers are lucky, he said, in that the public – and especially the young – have a genuine interest in and curiosity about the visible universe. Not all subjects enjoy the same levels of interest.

“If I am sitting at an official dinner, with people I don’t know, and they ask, ‘What do you do?’, if I answer, ‘I’m an astronomer’, then the conversation will flow and become very interesting.” On the other hand, if he doesn’t feel like talking much, he could also reply – as someone whose work draws on both physics and astronomy – “I am a physicist” and that quickly closes the conversation down.

For such reasons, Gustafsson is adamant that academics in all disciplines need to bring their research to the public and to do so in ways that get them interested. With his cheerfulness and natural enthusiasm, as well as that special teaching ability to ask the audience questions that genuinely disturb for a moment and put people on the spot, Gustafsson is eminently qualified for this necessary public work, which academics in all disciplines would do well to engage in.

Professor John Higgins is Arderne chair of literature at the University Cape Town. Bengt Gustafsson is Corresponding Fellow and Professor at the Nordic Institute for Theoretical Physics in Stockholm, Sweden