As mentioned in an earlier article, science is identifying patterns which are invariant in time and space. This allows scientific assertions to be tested by different people at different times and places. This requirement of invariance creates one limitation to the scientific method.
If a phenomenon is not invariant, it is not amenable to scientific description. In other words, if something happens a particular way only once, or strictly randomly, or only in specific regions of space, the scientific method cannot be applied.
Some scientists believe that all phenomena are invariant, so the difficulty will not arise. However, there is no particular reason why everything in the universe should behave consistently. It is an unscientific belief that things are such. Note that it might be the case that everything behaves consistently. We just don’t know that. And we can’t know that in a scientific sense. It is an unprovable hypothesis, ie. a belief.
This highlights one of the difficulties of science. Sooner or later, we always reach a point of belief – irrational belief. A theist believes in god. A scientist might believe that all phenomena are invariant. They are both irrational beliefs.
When a scientific theory mostly holds true but is known to fail in a particular situation, that situation is labelled a singularity. One example of a singularity is the centre of a black hole, where the mathematics of the general theory of relativity break down. The theory seems to work everywhere else in the universe, so it’s quite useful, but it doesn’t apply in a black hole. So, the fabric of space-time does not quite behave with invariance. Some people simply gloss over this issue, whilst other scientists understand that the theory is therefore incorrect and will eventually be replaced with something better, just as relativity theory itself replaced Newton’s laws of motion.
A black hole is an example of a singularity in space. Scientists also know that there is at least one singularity in time, namely the moment of the big bang. Physics describes things quite well from a time soon after the big bang; very soon indeed after the big bang. At present, I believe that theory has got a handle on things from a time of about 0.000000000000000000000000000000000000000001 seconds after the bang. Considering that was 13 or 14 billion years ago, most of time is covered, so again the theory is very useful. Like in the case of black holes, though, it is known to break down in that first fraction of a second. With further research, the theory might be developed to cover time even closer to the big bang. However, it seems unavoidable that the actual moment of the big bang will always remain a singularity.
Quantum physics has raised some other challenges for the scientific method. One is the uncertainty principle, which states that the position and momentum of a particle cannot both be determined precisely at the same moment. This is a fundamental characteristic of the quantum world, rather than merely a restriction due to current technical capabilities. To put it another way, physics has ascertained that there is a fundamental limit to how precisely we can know the state of things.
To complicate things further, in quantum physics a particle exists as a probabilistic wave function until it is observed. At the moment of observation, the wave function collapses and the particle’s attributes become decided. It is not that we are simply ignorant of the attributes until observation; rather, the particle actually exists in a probabilistic form, with all possible attributes, until the moment of observation. This means that the act of observing phenomena is not passive; making the observation actively affects the state of things. Strictly speaking, this means that no knowledge is purely objective, and yet objectivity is one of the foundations of the scientific method.
The behaviour of things at the quantum scale raises another significant difficulty regarding invariance: Quantum events can occur at random times. For example, an individual radioactive decay event occurs randomly, which means that it violates the requirement to be invariant in time. As with the uncertainty principle, it is not that we are simply missing some measurement which would tell us when the event will happen. Rather, the timing of the event is genuinely random and, fundamentally, cannot be predicted. Quantum physicists handle this difficulty by resorting to statistics. These random events collectively follow well defined probability distributions. Again, this allows the theory to be very useful, even if there are some specific things it cannot (and will never be able to) predict.
So quantum theory has declared that some things are fundamentally unknowable. Another word for things that are fundamentally unknowable is mystery. A mystic is someone who believes that the whole of existence is fundamentally a mystery. Given that the big bang is a fundamental singularity and that quantum physics underlies the whole of existence, it turns out that physicists are actually mystics!
