Scientists talk about gravity, mass and probabilities, atoms, Higgs boson, black holes and qasars. Certainly the universe seems to behave as if these concepts represent reality and so scientists are justified in the their assertions and predictions. Nevertheless the assumption that the concepts that scientists use represent reality is debatable.
The scientific method which has been a part of science since 17th century is a set of rules that scientists use to develop and test theories about the scientific view of the world. Basically, the scientist formulates a hypothesis (based on an earlier theory or as a totally new theory) and develops experiments to test the theory. The experiments produce observations which either support or do not support the theory.
If the observations agree with the theory they are said to support the theory. If they do not, they are said said to disprove the theory. So far, so black and white. An experiment may be challenged on many grounds. For example the search for the Higgs boson is not done by actually isolating candidate particles and looking at it directly. Instead the expected properties of the Higgs boson, perhaps its mass or energy, the way it interacts with other particles, or other more esoteric properties, can be used to deduce that, for example, in a particular experiment a peak at a certain point on a graph produced by a scientific instrument could only be the result of the presence in the apparatus for at least an instant of the required Higgs boson.
In a similar way, we don’t detect an electric current directly. Instead we rely on electromagnetic theory which predicts that moving electrons should produce a magnetic field and that magnetic field would interact with a static magnetic field of a permanent magnet perhaps to produce a force on the permanent magnet hence moving a needle. Behold! We detect an electric current. Actually what we see is the movement of a needle and we infer the electric current from that observation.
Sometimes the chain of inference is short, as in the electric current experiment, while in others it is very much longer. I expect that the detection of the Higgs boson falls into the latter category, but I could (easily) be wrong. It is apparent that the more links that there are in the chain of inference, the higher the likelihood that one of the links might be debatable.
So, faced with an experiment that supposedly tests a theory, the result does not absolutely prove or disprove the theory. If the experiment appears to show agreement with the theory, an opponent of the theory may cast doubt on the experimental method or in the theories that the theory being tested relies on. He or she would claim that the result doesn’t show what it purports to show. In addition he or she might point out that one experiment does not prove the theory as the next experiment could show the opposite. One experimental failure is enough to disprove the theory.
Or is it enough to disprove it? Not really because the proponent of the theory could claim that some currently unknown effect or other is preventing the experiment from producing the correct observations. So debate follows, more experiments follows, and in the end, a consensus is achieved. History will record that theory A was generally accepted until so-and-so’s experiment replaced it with theory B. Or that theory A was extended by theory B and confirmed by so-and-so’s experiment. Or similar. Much more black and white!
Scientists explain experimental results in terms of theories. For instance when sodium is introduced into a flame (perhaps in the form of sodium chloride – salt) and the light from the flame is passed through a prism then a bright yellow line is seen. Scientists explain this as the result of the transition of an excited electron from an elevated orbit to a lower one. This explanation depends on several, maybe many, other explanations, such as an explanation of what ‘excited’ means and what ‘electron’ means and what ‘orbit’ means. In many cases these explanations are based on mathematics, and an explanation is based on concepts each of which requires explanation.
So therein lies the hubris of scientists. Their attempts at explanation of observable facts is a bottomless pit of explanation on explanation. There is no ultimate explanation. The universe is and does what it is and does.
So, am I saying that science is pointless? No, I am merely saying that we need to be careful and not treat our explanations as anything other than very clever descriptions of those bits of the universe that we are have seen.
I like the analogy of the sheet. Suppose you have an object hidden behind a sheet. You are allowed to make pin pricks in the sheet, one at a time. The universe is the object behind the sheet and each pin prick is an observation. As you make more and more pin pricks in the sheet you see more and more of the object behind the sheet. You may discover that a line of pin pricks is showing red. You form a theory that behind the line joining the existing pin pricks, between the existing pin pricks and, with less certainty, beyond the end pin pricks in the line, everything is red. To check this theory you make a pin prick between two existing pin pricks and find that the new pin prick shows red. The theory is supported by this new observation.
Scientists have been creating these pin pricks for centuries and now have a pretty good idea of the shape of the universe (and a pretty holey sheet!). Nevertheless there are parts of the object behind the sheet, the universe, that they haven’t yet uncovered, and maybe never will.
As an example of the type of thing that I mean, consider the so-called dark matter. Scientists appear to have pretty much discovered what constitutes matter but they can’t account for some aspects of certain large scale phenomenon observed in the universe and have hypothesised a new type of matter called ‘dark matter’, which doesn’t appear to interact with normal matter except gravitationally. It’s like suddenly finding some pin pricks showing blue in a line that is otherwise red. Something unexpected that needs explanation.
I accused scientists of ‘hubris’ above. That’s not entirely fair as hubris implies arrogance and while scientists confidently create explanations for phenomena that they study, I believe that most would concede that their explanations could (with very low probabilities, I would guess) prove to be erroneous.