The Limits of Science
By Darren Arndt, BSc
Copyright 2021
Introduction
1 Technological Limits of Science
As science has advanced over the centuries, it has become more
and more dependent on technology. While some observations are
possible with the naked eye, such as reading a thermometer or a
stopwatch or the colour of a chemical byproduct, most areas of
scientific investigation now require advanced technology to provide
greater levels of observational precision.
For example, astronomy is limited by the capabilities of telescopes.
Galileo’s primitive telescope allowed him to see the moons of Jupiter
and the rings of Saturn. The Hubble Space Telescope can see
galaxies 10 billion light years away or more. The next generation of
space telescopes will exceed Hubble’s capabilities significantly.
Similarly Van Leeuwenhoek’s simple microscope progressed to
modern scanning electron microscopes able to produce over a
million times magnification.
Technological limits are relatively temporary. As technological
improvements are made, the limits of science are pushed back and
new discoveries become possible. When scientists speak about
science explaining everything eventually, they are usually referring
to the progress of technology to push back the boundaries of
discovery. However, technological progress never removes those
boundaries -- it just moves the boundaries to new positions.
Technological limits are real and are always present in science.
They prevent scientists from answering certain questions today
until the technology progresses. The Higgs boson was proposed in
1964 but it could not be detected until 2012 using the latest tech-
nology at the CERN Large Hadron Collider. X-ray astronomy could
not progress until the advent of satellites because the atmosphere
blocks x-rays from reaching the Earth’s surface. Current technology
always forms one very real boundary of scientific knowledge.
2 Physical Limits of Science
For example, nothing can be cooled below absolute zero. Once all
heat is removed so every substance becomes a solid, there is no
more heat that can be removed. No scientific technology can break
that physical limit. This may seem trivial as who would ever want
something to be colder than absolute zero anyway?
Other physical limits are not as trivial however. Spaceships can be
designed to travel faster and faster but never faster than the speed
of light. That limit would be very helpful to overcome for interstellar
travel but it cannot.
In the computer world, reducing the size of electronic circuitry is
limited by quantum tunneling. When the conducting path is about
1 nanometer (or one billionth of a meter), the electrons can oc-
casionally move across the insulating barrier into the neighbouring
conductor and confound the functioning of the circuit. Circuit boards
must stay at a large enough scale to prevent electron tunneling from
occurring even if the technology is available to make the circuitry
smaller.
The medical sciences are limited by death. Despite incredible
advances in disease treatments and amazing resuscitations that can
occur minutes after a heart stops beating, once death occurs it is
stubbornly permanent. There is no treatment for corpses that can
return them back to life. Two hundred years after Mary Shelley
wrote her book Frankenstein, it remains firmly on the fiction shelf of
the library.
The physical universe also limits us in the dimension of time. Time is
a one way street. We cannot go back in time and undo our regrets.
We cannot unbreak a broken egg and have it reassemble in front of
our eyes. As Richard Feynman taught in his 1960’s lecture
The Distinction of Past and Future, “In all the laws of physics that we
have found so far, there doesn’t seem to be any distinction between
the past and the future.” No scientific law requires time to move
forward and no law forbids time from moving backwards. Our
experience however tells us time only ever moves in one direction. It
appears to be a physical trait of our universe that science has not
explained and cannot change.
Time is also relevant in terms of predicting the future. Some scientific
laws are excellent at predicting the future or even going back in the
past. Newton’s laws of gravity work very well going forward or going
backward, as long as it is not near a massive star where the rules of
general relativity kick in. We know the conjunction of Jupiter and
Saturn in December 2020 was the closest those planets have been
in our sky since 1623 because Newton’s laws can be modeled back-
wards quite accurately. We also know they won’t be that close again
until the year 2080 because Newton’s laws can be modeled forward
as well. It was this deterministic success of Newton’s laws that led
French scientist Laplace to declare in 1814 that all branches of
science would one day have this level of predictive success.
Unfortunately it turned out Laplace was wrong. Most areas of sci-
ence have nowhere near that level of predictive ability. Weather
forecasting is an excellent example. Meteorologists can predict the
weather 1 or maybe 2 weeks in advance, but not much further than
that. No one would believe a weather forecast 3 months in advance
and certainly not a year in advance. It would be laughable to ask for
the weather forecast for your city during the next close conjunction
of Jupiter and Saturn in 2080!
Why are meteorological models less accurate predictors than planet-
ary orbit models? Is it because meteorologists are lacking sufficient
technology to predict the weather? No, there are lots of weather
satellites, Doppler radar transmitters, automated weather stations
and complex computer models employed to this end. Is it because
the current theories of meteorology are lacking? No, weather pro-
cesses are quite well understood. It is simply because weather
systems are far more complex than planetary orbits.
Meteorology is an example of a complex non-linear system. It is a
case study for chaos theory and the Butterfly Effect. Weather is
difficult to predict because very small perturbations in the initial
conditions have huge effects on the outcomes in the future, such
as a butterfly flapping its wings affecting the behaviour of a tornado
weeks later. This is a physical characteristic of this system and it
limits the predictive accuracy that science can achieve.
There are many other complex systems. COVID-19 has demon-
strated this clearly in 2020 as numerous infectious disease models
have failed to accurately predict COVID-19 infection or death rates,
nor have they accurately predicted the effects of policy mandates
such as social distancing or face masks. Infectious diseases and
their interactions with a population of human immune systems are
very complex indeed.
An example of a mechanical chaotic system is the motion of a
double pendulum, or a pendulum with another pendulum attached to
its end. This video shows six examples of an identical starting
pendulum position that quickly leads to six very different behaviours.
Predicting double pendulum motion is nearly impossible beyond a
few seconds in the future. It is not because we lack a theory of
pendulum motion and it’s not because we lack sufficient pendulum
technology. It is entirely due to the complex nature of this system.
Physical limits of the universe therefore limit science’s technological
capabilities and its predictive precision. While medical treatments,
meteorological models and disease models are likely to improve in
the future, they will never remove these physical limits. There is
nothing science can do to make this complexity go away.
3 Theoretical Limits of Science
The Big Bang Theory begins with a singularity when all the energy
and matter of the universe is contained in a tiny region where space-
time curvature becomes infinite. It is infinitely small, infinitely dense
and infinitely hot. In other words, the mathematical formulas meet
another divide-by-zero barrier. Physics can explain what happens
a tiny fraction of a second after singularity, but it cannot explain what
happens at the Big Bang’s singularity nor can it explain what
happened before it. This is the single biggest limitation of any branch
of science. Despite all of its incredible successes, science cannot
explain what happened at the absolute beginning of the universe.
It is an impenetrable wall impeding any attempt at scientific
investigation.
There are a couple other limitations of science that could fit in either
the physical category or the theoretical category. Regardless of your
preferred categorization, they are limits nonetheless.
A significant limit from quantum mechanical theory is Werner Heisen-
berg’s Uncertainty Principle. This states that there is a limit to the
accuracy one can measure a particle’s position or momentum. The
more accurate the measure of position is, the less accurate the
measure of momentum must be, and vice-versa. This is often ex-
plained as an observer effect, in that by shining a photon on a small
particle, the photon will convey energy to that particle and change its
position and momentum in the act of measuring it. However the
uncertainty principle is fundamentally a derivation from the wave-
particle duality of the quantum mechanical world. Because particles
are also waves, the edges of the particles get a bit blurry and the
motion of the particles becomes wave-like, making the specific loc-
ation and motion of the particle difficult to measure with precision.
Regardless of which explanation one prefers, this is a very real
limitation of our ability to measure the quantum world.
Another limit from the Big Bang Theory is the edge of the universe
and the beginning of time. Because light travels at a fixed speed,
when we look at objects in the sky we are seeing them as they
appeared when the light left them. We see the moon as it was 1.2
seconds ago, the sun as it was 8.3 minutes ago, the nearest star
Proxima Centauri as it was 4.2 years ago, and the nearest spiral
galaxy Andromeda as it was 2.5 million years ago. Therefore tele-
scopes should not be able to see anything further back than the Big
Bang, about 13.8 billion years ago. Our current telescope technology
is getting close to that limit and the next generation of space tele-
scopes should provide the ability to conclusively confirm or disprove
this time and distance limit. It is interesting to note that the Steady
State Theory which was more popular among cosmologists until the
mid-20th century provides for no such beginning or edge of the
universe. Therefore this is a theoretical limit which may also be a
physical limit as long as the Big Bang theory continues to prove
correct.
Lastly, theoretical limits exist when observations cannot be explained
by any existing laws of science. Dark matter and dark energy are the
best current examples of this.
Dark matter was first postulated to explain the observed rotation of
galaxies. There must be more mass in the galaxies than what is
visible in order to match the predictions of the current law of gravity,
which is Einstein’s General Theory of Relativity. This extra matter
must be both massive and invisible to us, meaning it does not react
to light. There is no such substance currently known to science. It
may be explained in the future by the discovery of a new subatomic
particle or a change to the theory of gravity such as Modified
Newtonian Dynamics, but the answer is currently unknown.
Similarly, dark energy was postulated to explain the observations
that galaxies are accelerating away from us. There is no known
repulsive force that could act at such large distances. It is effectively
behaving like anti-gravity but anti-gravity only exists in science
fiction stories. It resembles Einstein’s cosmological constant which
he later discarded. Dark energy could mean our understanding of
gravity is incomplete or the Big Bang theory is incomplete or there
is another undiscovered subatomic particle out there. It is currently
a scientific mystery.
4 Limits of Scope
Despite Peter Atkins’ belief that “there is nothing that the scientific
method cannot illuminate and elucidate,” the scientific method
contradicts him quite clearly. Science is limited to observable
physical events. Anything that is not physical and not observable is
not within scope of the scientific method. The early scientists
understood that science had clear limits in scope, unlike modern
scientific materialists.
One area outside of the scope of science is ethics. What branch of
science defines which human behaviours are good or bad? Which
natural law requires scientists to be honest when reporting their
findings in scientific journals? Biological natural selection seems to
care only about passing one’s genes to the next generation, so if
lying to your date results in having sex then lying must be good.
Survival of the fittest implies the stronger can eliminate the weaker
members of a population, a scientific principle that Hilter’s Nazis
took to the extreme in their death camps. Great evils have been
committed when science alone becomes the basis for morality.
Ethics are not physical nor observable and yet they are essential
to society, including for a well-functioning scientific community.
Another example of something non-physical is God. Since most
concepts of God are that of a spiritual and supernatural being, then
God must be outside the scope of science. Isaac Newton realized
this and in his Principia Mathematica wrote, “The most beautiful
system of the sun, planet and comets could only proceed from the
counsel and domination of an intelligent and powerful Being.”
Newton felt his discoveries regarding the laws of motion and gravity
did not disprove the existence of God, but rather supported his
existence. Newton realized that God existed outside of these
physical laws. Similarly, Descartes felt that the natural laws of
physics could be deduced from the characteristics of the God who
created those laws. He saw the law of conservation of momentum as
being consistent with God’s unchanging nature. Scientific discovery
has a clear boundary that limits it to the study of the physical world.
Anything metaphysical is out of scope. One can choose to believe or
not believe in God, but science cannot directly inform those beliefs.
There are many other things outside the scope of science such as
beauty, hope, purpose in life, the afterlife, and on and on. Because
these things are outside the scope of science does not make them
unimportant. In fact they may be more important than many of the
topics science can address. As Einstein famously said, “Not every-
thing that counts can be counted, and not everything that can be
counted counts.”
Conclusion
Science has always had boundaries and will always have them. Two
types of boundaries are relatively temporary: technological and
theoretical boundaries will eventually be pushed back. Two types of
boundaries are permanent: physical and scope boundaries are not
going anywhere.
The temporary boundaries are called the frontiers of science. It is
those areas of science where unanswered questions are being
actively investigated and new technologies and theories are being
developed. It is where scientific knowledge is constantly changing,
improving and expanding. These boundaries however never
disappear. Their positions will change but their presence remains.
Returning to Peter Atkins’ statement that “there is nothing that the
scientific method cannot illuminate and elucidate,” let’s test it out.
How can the scientific method illuminate the following questions?
What will the weather be like 5 years from today?
What career path will I find most fulfilling?
Should I steal my neighbour’s sports car and take it for a spin?
Will I go to heaven after I die? If so, what is heaven like?
Should I get high with my buddies this weekend?
What is the most beautiful symphony ever composed?
What is the purpose of my life?
Should I kill myself?
These questions range from trivial to profound to tragic. Science
can answer none of them.
Many scientists will offer loud and bold answers to many of these
questions but those answers only reflect their personal beliefs, and
personal beliefs of scientists do not equate to science.
Erwin Schroedinger, one of the fathers of quantum mechanics,
summarized it like this:
I am very astonished that the scientific picture of the real
world around me is deficient. It gives a lot of factual infor-
mation, puts all our experience in a magnificently
consistent order, but it is ghastly silent about all and sundry
that is really near to our heart, that really matters to us. It
cannot tell us a word about red and blue, bitter and sweet,
physical pain and physical delight; it knows nothing of
beautiful and ugly, good or bad, God and eternity. Science
sometimes pretends to answer questions in these domains,
but the answers are very often so silly that we are not
inclined to take them seriously.
Anyone who believes science can answer all of life’s questions is not
only being naive and wishful, but to borrow Richard Dawkins’ term,
they are the ones who are being delusional.
