A long philosophical debate, which is perhaps my most favourite topic in philosophy, is the issue of realism vs. instrumentalism of science. I find this issue fascinating not only because my career is centred around science, but also because it effectively covers many essential principles of metaphysics and epistemology.
Realism is the view that the theories of science and the entities they introduce really describe what actually exists in nature. In other words, based on scientific realism, atoms, electromagnetic waves, quantum phenomena, fundamental particles, and all other such entities really exist (as long as the scientific theory is true of course). Opposite to realism, there is anti-realism, which suggests these theories and entities do not correspond to the objective reality of entities in nature.
On the contrary, scientific instrumentalism has a very different approach to the theories and entities introduced by science. Instrumentalism sees the focus of realism as irrelevant and instead suggests that science is an instrument and it should be evaluated based on how good it can produce predictions and usable results. This is the view that I have come to support after much thinking.
Before addressing the fundamental philosophical problem with realism, I want to explain a very concrete problem with the scientific method without going to existential and metaphysical discussions. Let’s just examine the scientific method. It is explained in many shapes and forms, but without going to too much detail, the scientific method consists of identifying some problem (observation, inquiring, gathering data), forming a hypothesis, deducing the logical consequences of the hypothesis, and empirically testing those predictions which then either confirm or disprove the hypothesis after many trials and ideally numerous predictions. It is immediately obvious that science inherently depends on logic and human reasoning. The connection between a testable prediction and a theory is entirely based on reasoning alone. For example, electromagnetic waves are a conceptual entity. One cannot test the existence of an abstract entity. Instead, human reasoning is used to connect that idea to a testable prediction. Even if one accepts that there is an objective reality, it is not determined whether our reasoning connects the “right theory” to the “right prediction”. But I must admit that I am not entirely confident on this issue because it can be argued that logic itself is an empirical science. But when was the last time you empirically tested a theorem in your mathematics class (whatever that means)? This issue of the origin of logic is an interesting one which I like to pursue further, but as far as I can tell mathematics does not seem empirical to me. Thus, the whole scientific method as a means of discovering some “objective reality of nature” breaks down.
However, I find a deeper problem with the realistic point of view, and this is more of a metaphysical approach. In other to attempt to find out whether science corresponds to reality, we must clearly define what we mean when we ask whether an entities “exists”? One can define existence based on perception or based on reasoning. In other words, I can define existence such that something exists if I perceive it, or it exists if I think it. So let’s backtrack a little and see what it is we are trying to answer and thus come up with a good definition. I want to find out whether scientific entities correspond to the outer world that I experience around me. So what is the outer world? Let’s start from what I know. I know that I am some conscious agent. That is all I know. Next, I observe a world around me. Of course what I observer does not necessarily exist in the sense that I do as a conscious agent. All of this world, including other seemingly conscious agents, are all in my perception and can be anything… an illusion, a dream, a virtual reality, etc. Now, I do not have access to anything outside of my perception and so I define knowledge within my perception. So at first it seems that a good definition for existence is direct perception. However, it quickly becomes obvious that the world around me is not what I directly observe it to be. For example, 5 years ago something funny happened. The universe got fuzzy and so I started wearing glasses so I can operate better in the transformed, fuzzy universe. But my reasoning tells me that the universe did not change, but it was my eyes, my perception, that changed and that belief shapes my reality. Another example is what we call optical illusions. In the case of optical illusions, such as holograms, my reality does not come from direct observation but again from reasoning and observation together. The point is that in constructing my reality, perception and reasoning are inseparable. So ultimately I am a conscious agent and the reality around me is a reality constructed in my mind through my perception and reasoning. With this definition of reality, how does science correspond to reality? The answer is that science creates reality. When I see the effects of atoms under the microscope, my perception and reasoning create a new reality. This is exactly analogous to the examples I gave earlier. Therefore, any scientific theory becomes a new reality, and the realism/anti-realism debate becomes completely meaningless. Instead, the focus of science becomes the evaluation of different versions of reality based on their usefulness. The new realities of atoms, electromagnetism, and quantum mechanics (along with all other successful theories) are indeed more superior to their alternatives (so far at least) in the sense that they have been the most useful in making a consistent, predictable, and harvestable reality for the reasoning and perception that created them.