In the history of science, we have discovered a sequence of better and better theories or models, from Plato to the classical theory of Newton to modern quantum theories. It is natural to ask: Will this sequence eventually reach an end point, an ultimate theory of the universe, that will include all forces and predict every observation we can make, or will we continue forever finding better theories, but never one that cannot be improved upon? We do not yet have a definitive answer to this question…
— Stephen Hawking & Leonard Mlodinow, The Grand Design, p.8
From early childhood, we all learn about the principles of science in some way or form, be it from a teacher, a family member, or just pure observation. In school, for example, we learn facts such as the Earth spins, DNA has a double helix shape, and electrons orbit a nucleus in shells. With so much knowledge perpetually being absorbed by us at high rates, we often fail to reflect upon the nature of this knowledge; where does this come from? what exactly do these statements imply? and how accurately do they paint the picture of existence? The field which attempts to answer these questions is the philosophy and methodology behind science, and a key issue for this field is the perception on what science tells us about the world. Two schools of thought which emerge on this subject are ‘Realism’ and ‘Instrumentalism’. Throughout history and especially in recent times, the popularity pendulum swings between the camps of Scientific Realism and Scientific Instrumentalism, and is currently situated near the vicinity of the Realists. The case for instrumentalism, however, remains strong and relevant. This essay attempts to highlight the main points of instrumentalism and provide an argument of its validity.
First and foremost, what are instrumentalism and realism?
There is no one definition of scientific realism, and often problems arise as it is characterised differently by different authors, but the general description the Stanford Encyclopaedia of Philosophy states is that which is concerned with the ‘actual epistemic status of theories’. Realists essentially believe that scientific descriptions of the phenomenon have a true-false value and describe something which actually exists. They believe the theories, statements, and formulas accurately represent (or at least attempt to) exactly what the world is. Austrian-British philosopher Karl Popper’s view on the core premise of scientific realism as follows:
Scientific theories are either true or false, and the terms of a true theory refer to unobservable but genuinely existing entities
Scientific Realists take acceptance of a theory or measurement to imply truth. Theoretical terms such as electrons and other unobservable entities do not have their existence questioned. For example, the rest mass of an electron measured to be .00055 am is assumed by the realist to be a measurement of a real entity. Scientific Instrumentalism, on the other hand, is the view directly opposing Realism. It rejects the above premise and does not claim to reveal reality beyond experience. The instrumentalist believes that theories about science should be considered just tools or instruments for making observable predictions. They attempt to explain a phenomenon in the best way possible without confirming the exact validity of the phenomenon. In a similar way, formulas and functions are just models which predict the behaviour of a phenomenon. The ability to verify a theory as true or false for an instrumentalist is irrelevant, the functionality of a theory instead lies on its predictive scope and applicability. According to an instrumentalist, Newton’s gravitational laws, Planks constant, and the Bose-Einstein condensate model for examples are all just useful tools for understanding the world around us and are used to implement in calculations.
Scientific Realism may seem intuitive to those somewhat familiar with science due to the easy provability and reliability of some theories. If I drop an apple it falls to the ground, no matter how high, low, fast, slow, whether I’m on a mountain or in the planes, the apple falls down. So obviously, there must be a downward force acting on the apple? Isn’t it unquestionable that Gravity has to be real to be pulling the apple down to the centre of the Earth? Let gravity exist; what is it then? According to Isaac Newton, it lies in this equation:
F=G (m_1 m_2)/r^2
(where G is the gravitational constant, m_(1 ) m_2 are point masses, and r is the distance between them)
This abstract algebraic equation according to a realist living in the 18th century is a truth which describes how the real, existing entity of gravity functions. Fast forward two centuries and this theory were shattered with Einstein’s work, and what exactly is the fundamental issue with scientific realism: History has proven time and time again that what we thought was real and accurate is actually not. Through the course of time, theories and formulas are either blatantly rejected or constantly replaced with ones claiming to be ‘more accurate’. This is inherently problematic for realists as even if they firmly stick to their beliefs, it raises the question of whether we will ever reach a completely accurate theory of everything. For that to happen one must assume there is a ceiling limit to available knowledge. Furthermore, it seems impossible to determine whether or not one has reached that stage: It’s impossible to prove that our new ‘perfect’ theory is actually perfect and cannot be disproved.
Take the geocentric model which places the Earth at the centre of the universe. This system was widely accepted for centuries and hence considered a ‘truth’. A realist would, therefore, agree that the theory describes a phenomenon actually existing, and agree that the Earth is actually at the centre of the universe. Part of the widespread literature on this Earth-centred subject was Ptolemy’s geocentric model, which was used in the construction of astrological and astronomical charts for over 1500 years. Let’s say there were two rival sailors in Ancient Rome both attempting to reach a new continent first. The realist sailor uses the geocentric astronomical chart because he believes it true, and the instrumentalist sailor uses the same chart but only because he finds it useful, not because he necessarily believes it true. From the perspective of a 21st-century reader, one would find the instrumentalist more reasonable in his beliefs and use of science. The same holds true in another case this time somewhere in the 16th century where the new Copernican Heliocentric system was presented. The first sailor uses the model because he believes it true, and the second because he finds it far more useful than previous systems; the instrumentalist is still able to achieve utility without confining to the notion of truth and false. The same is seen with theories on gravity. Newton’s model and laws of mechanics and gravity have been proven false (false by replacement with another theory) yet the equations are still widely used in calculations. NASA still uses Newton equations for most space shots, and only General Relativity when further accuracy is required such as in GPS systems. One might say but how can we use systems which are false and outdated? The instrumentalist offers the solution: There is no truth or false in these theories, one is just a more accurate representation of the world than the other. There is no need at all to view a theory strictly in the sense that it must be true or false. A realist may scorn and accuse the instrumentalist as being anti-science, as not being dedicated to the quest for knowledge. The instrumentalist, however, is essentially keeping an open-mind, remaining agnostic to existential properties of a scientific result, and is focused more on the best, most effective way to communicate and disperse knowledge.
Einstein’s theory of General Relativity is often represented with a gravitational object curving a sheet around it much like a person standing on a trampoline. This offers us a useful way of visualising gravity and understanding how it works, however, one cannot actually visualise gravity. There isn’t actually a giant cosmic gridded sheet laying beneath all our universal objects. We hence take an instrumentalist approach here and regard the visualisation as a tool or instrument for our understanding and use. Is gravity a force or a consequence of the curvature of space-time? Once again there is no 0 or 1 value; these are merely words attempting to reconstruct the abstract into the concrete language. Modern science after Einstein further hurts the case for realism. Quantum Mechanics is filled with uncertainty and new developments and was and in parts still is so new and unintuitive that an instrumentalist approach is rather necessary to take. This view is epitomised by solid-state physicist David Mermin’s famous quote “Shut up and calculate!” This approach to Quantum Mechanics has in fact brought rise to numerous discoveries and advancements. A scientific realist would halt research so that they can be confused and frustrated about the vast contradictions arising.
It is certainly possible that a quantum theory can replace the Einstein theory, and who’s to say that another century down the line there isn’t a new theory which would replace that! With so much doubt and expanding knowledge, it seems irrational to believe that what we measure and describe now is the truth itself. As recently as 2010, Stephen Hawking and Leonard Mlodinow, two of the greatest theoretical physicists of modern times, set forth the view of ‘Model-dependent realism’ in their book ‘The Grand Design’. The view focuses on scientific models of phenomena and claims it is meaningless to discuss the ‘true reality’ of a model as it is impossible to be absolutely certain of anything. Although the term ‘realism’ is used, the definition screams instrumentalism, and fundamentally holds the same notions that a theory should be evaluated by how effectively it explains and predicts phenomena. This model represents the closest evaluation behind the nature of science, and elegantly displays the endless possibility of improvement and enlightenment. It’s near impossible to tell what the future of science holds, and what it will mean, but what we know for certain is that we know nothing for certain.
By: Arya Krishnan