I refer to Dr Stefen Tan's letter regarding the debate on scientists and religionists. Despite portraying himself as someone with scientific credentials (assuming mathematics is considered as a science, which is highly debatable), he nevertheless betrays a breathtaking ignorance on the scientific method.

He begins by claiming that scientists have no right to decide which postulates (i.e. assumptions) in science are permissible, on the basis that postulates are not testable. While this might be true to a certain extent in mathematics, postulates in science are patently testable once one accepts
the existence of an external reality. Einstein's theory of special relativity assumes that the speed of light is constant, and that nothing can exceed it, an assumption which has been proven countless times through experiments.

Similarly, Maxwell's electromagnetic theory assumes that magnetic monopoles do not exist, and indeed such objects have never been observed in nature. If a postulate turns out to be false, then the theory needs to be revised. And if scientists are not the right people to decide which scientific assumptions are acceptable, who should?

Like many religious fundamentalists, he also makes the fallacy of mistaking something which is non-religious as being anti-religious. Science is completely impartial with regards to religious belief, and scientists do not make assumptions regarding the existence or non-existence of God, Allah, Krishna or the Jade Emperor while carrying out scientific work. This is the reason that scientists can work together even if they have different creeds and beliefs. It is, moreover, not the fault of scientists if their findings are contrary to certain religious beliefs.

He further castigates scientists for opposing the teaching of the Intelligent Design (ID) Theory, which is not science as it cannot be falsified. Falsifiability is one of the cornerstones of any scientific theory, ie, there must exist counter-examples which will disprove a theory. For example, as mentioned earlier, the theory of relativity will be disproved if objects moving faster than the speed of light are discovered.

ID argues that biological systems are too complex to be explained through natural laws: this is impossible to falsify, as there will always be systems which are not fully understood at the frontiers of science. The moment that a theory is found to explain the 'unexplainable' phenomenon, then ID proponents will just shrug their shoulders and move on to something else.

In addition, a quick glance at the SPM science syllabi reveals this: in Physics, the latest discovery discussed is the 1913 Bohr model of the atom; similarly, in other subjects, the only things which are taught to students have all been well-established for decades. Thus, arguments to teach ID in school in order to 'show both sides of the controversy' are nothing more than naked attempts to teach religion in a science class. If ID is to be taught in science classes in order to 'show the full picture', then perhaps religious classes in schools should follow the same example by teaching other religions and not only theirs.

Tan also betrays his knowledge of science further by comparing scientists' inability to actually see nuclear particles with the naked eye, with their alleged refusal to acknowledge the existence of God even if he turns up in front of them. As the scientific method has to do with describing nature, one simple consequence is that it allows humankind to manipulate nature, and furthermore any scientific theory cannot contradict other facts we know about nature.

Thus, while one might try to deny the existence of nuclear particles, one cannot deny that the functionality of, say, nuclear weapons is dependent on the assumption that nuclear particles exist. If a skeptical scientists sees God appearing before him, he may indeed attempt to dismiss it as an illusion or hallucination. However, if the said apparition of God strikes him with lightning (and hence establishes itself into a reality beyond the visual sense), then he is forced to acknowledge the existence of this being.

Finally, he makes a sweeping dismissal of macro-evolution, firstly by invoking the authority of Gregor Mendel, the father of modern genetics. Unfortunately for him, he is citing a scientist who lived over a hundred years ago, prior to the revolutionary discoveries of 20th century such as the discovery of DNA and molecular biology. Mendel would not have had the knowledge to know better. Tan's dismissal, specifically, of parts of evolutionary theory which 'link man to the primates' reveals that his concern is not of a scientific nature, but is thoroughly religious.

He claims that because 'counter-examples' have been found for macro-evolution, thus it has been proven false. This, again, shows an ignorance of the scientific method. Science does not progress until the scientific community as a whole agrees by consensus as to the validity of a new theory, which fits the facts better than an older theory. At this point in time, macro-evolution is by far the best explanation for observed phenomena in biology, even though it might not be perfect in its details. That is the normal state of scientific theories which seek to attain the best description of nature through the scientific method.

While there might be evidence contrary to established notions of macro-evolution, these are not sufficient to cast out the theory until large numbers of strong evidence have been found. In any case, macro-evolution is a theory which is still in (pardon the pun) evolution: its details can be modified to fit new evidence. While religious people often complain that science is an atheist conspiracy to disprove the existence of God, scientists have in the past shown a willingness to accept evidence that can be interpreted to support the existence of God, such as the Big Bang theory of the Universe.

Regarding the existence of miracles, a scientist would not discount the possibility of miracles occurring but rather there is no way to systematically study such supernatural phenomena to establish it in a scientific manner (or rather, all such previous attempts have failed). The burden is on the believers of miracles to prove that the occurrence of miracles are beyond the realms of probability and statistics, rather than on scientists to disprove them.

The writer is attached to the Department of Physics and Astronomy, University College, London.