8.8 Scientific Realism and Anti-Realism (Instrumentalism)


By the end of this section you will discover:

  • The difference between scientific realism and anti-realism.
  • Speculations about the nature of science itself.
  • Whether science is better understood as a metaphysics or as an epistemology.
  • Strengths and weaknesses of realism and anti-realism.

Do the findings of science tell us something about the real, existing universe? Or are they merely a language for describing our human experience? In other words, does science get us to metaphysics, or is it better understood primarily as a form of epistemology?

Most of us likely were taught that science tells us about nature and the universe that exists outside our minds. This is Scientific Realism, “the traditional view that science is capable of giving us true accounts of the world and that the entities that play a role in our best scientific theories actually exist independent of our conceptual frameworks.” (Lawhead, op. cit.)  In this view, unobservable things like quarks and black holes, in addition to being the posits of scientific theories, actually exist in the physical universe. This view is familiar, but it does involve the kind of inductive leap from what is appearing in our minds to what might exist outside our minds, a leap, as we saw in the epistemology chapter, was partially accepted as possible by Locke but quickly denied by Berkeley, Hume, Kant, and many later epistemologists. Recall that Kant said that we cannot know the noumenal, that which might exist outside our experience, only the phenomenal world within our experience.

A strong argument put forth by the Realists is the “No-miracles” argument. It reads as follows:

  • Our best science is very good at making successful predictions
  • The best explanation for this success is that our methods are accurate, our theories are true, and the entities they describe exist
  • Anything else would make our success seem miraculous
  • Therefore scientific realism is true

This argument uses a form of reasoning called abduction or “inference to the best explanation” which means that it starts with an observation or set of observations and then seeks the simplest and most likely conclusion from the observations. It argues that if science was not describing an actual, real world outside of ourselves, then its success at theorizing and predicting the way the universe works would be completely inexplicable, or miraculous.

Scientific realism can be understood in three ways:

  • The Ontological (metaphysical) proposition is that there really exists an actual world outside of our human experience. This idea rejects the contention of the idealists that we cannot get to a mind-independent reality and holds that science gets us there.
  • A Semantic (language) proposition that holds that scientific theories should be taken literally and can either be found to be true or false. This implies that science is more than just useful language for organizing our experience but can be found to either correspond or not correspond to the real world outside the mind.
  • An Epistemological proposition is that most of science’s claims are true, that they give us knowledge of the real world outside our minds.

It’s important to remember that realists make these claims for “mature” theories, theories long established that have undergone experimental tests and withstood falsifiability. Realists hold that although these theories might not be fully proven, they nevertheless provide us with good approximations of the truth and will someday be shown to have been completely accurate.

Ponder if you will…

If a theory has succeeded in advancing our knowledge of the world, then which is more likely the case:

  • That the theory is giving us a pretty good approximation of reality, or
  • That the theory does not reflect reality but just happens to work successfully?

For example, consider “dark matter”. We have yet no way of observing or testing this hypothesis, but scientists have noted that the theory works very well to explain certain gravitational effects already observed that resist other explanations. Thus, the realist would argue that, although not yet fully proven, this theory

1) tells us something about the ontological universe “out there,” that it

2) is a proposition that we should take literally, and that it

3) is the best approximation of the truth about this phenomenon.

Scientific Anti-Realism, also called Scientific Instrumentalism, on the other hand, is the claim that we cannot know that science gives us an accurate picture of a real, physical world but instead is a great language whereby we can discuss and make predictions about our experience. This suggests that science is best considered a useful tool for modeling and prediction, but not a way to get to reality. Science makes claims about our experience of the world, claims that are quite useful for the advancement of scientific knowledge, but not useful as a metaphysical theory of reality. This theory also suggests that we should not ask whether scientific theories are true or false, but instead ask the more pragmatic question of whether they are useful or no longer useful for various scientific endeavors. Anti-Realism can take many forms, but most prefer to retain a healthy skepticism about scientific claims. This is especially the case for objects (like dark matter) that cannot be observed.

In the philosophy of science as in epistemology, instrumentalism is a methodological view that ideas are useful instruments, and that the worth of an idea is based on how effective it is in explaining and predicting phenomena.

According to instrumentalists, a successful scientific theory reveals nothing known either true or false about nature’s unobservable objects, properties, or processes. A scientific theory is merely a tool whereby humans predict observations in a particular domain of nature by formulating laws, which state or summarize regularities, while theories themselves do not reveal supposedly hidden aspects of nature that somehow explain these laws. Instrumentalism is a perspective originally introduced by Pierre Duhem in 1906.

Rejecting scientific realism’s ambitions to uncover metaphysical truth about nature, instrumentalism is usually categorized as antirealism, although its mere lack of commitment to scientific theory’s realism can also be termed nonrealism.  Instrumentalism merely bypasses debate concerning whether, for example, a particle spoken about in particle physics is a discrete entity enjoying individual existence, is an excitation mode of a region of a field, or is something else altogether. Instrumentalism holds that theoretical terms need only be useful to predict the phenomena, and the observed outcomes.

There are some strong arguments in support of Anti-realism.

First, realism makes an inferential and unprovable jump from the contents of our minds to something that exists outside of our minds. To recall our chapter on epistemology, whereas Locke believed that we could make claims about objects outside our mental experience, the so-called primary qualities of objects, later epistemologists like Berkeley and Hume accepted the fact that whatever we can say about objects is purely subjective, a description of what appears in the mind, not of anything outside it. Kant would reinforce this contention with his distinction between the phenomenal (that which appears in the mind and can be discussed) and the noumenal (whatever exists outside of the mind and remains unknowable).

Also, anti-realists also point to the fact that theories have been wrong quite often in the past and therefore should not be held to have been grounded in reality. For example, ancient theories of the solar system held that the earth was stationary, and the stars and planets and sun and moon revolved around the earth. This may have been a useful explanation of our experience of the skies at one time, but it is no longer held to be true. Kuhn reminds us that each period of “normal science” holds to certain theories until those theories no longer stand up to new discoveries. Certainly, no one wants to say that the earth actually was stationary until the geocentric theory gave way to the heliocentric theory, and then the earth began to revolve! Kuhn reminds us that theories are theories. They are useful for a time but should never be taken to be definitive about the reality of the world outside our minds.

Anti-realists argue as well that science ought not to be concerned with metaphysics. To limit science to language about what exists is to deny science the flexibility of creating useful theoretical models. As Lawhead puts it, the question naturally arises, “How can scientific theories be such useful guides if they do not tell us what the world is really like?” The anti-realist replies that a theoretical entity can be useful even though it does not refer to anything real. For example, we often hear statistics such as “The average American family has 2.4 children.” Obviously, there is no such entity as the average American family, for there is no family that has 2.4 children. However, the construct of “the average American family” is a useful one for economists and social planners. Similarly, anti-realists claim that objects like electrons, genes, and DNA molecules are theoretical constructs that serve a scientific purpose without necessarily being real. Finally, anti-realists argue that the pragmatic usefulness of a scientific model does not dictate that it is giving us the one, true story about the world (Lawhead).

Realists might counter with arguments of their own.

First, realists argue that the progressive nature of science indicates it is coming closer and closer to a true depiction of reality. If one does not hold this, then one is forced to the conclusion that the scientific understanding of the world we have today is not better than that, say, that of the middle ages, merely different. Few would want to argue that we have not gained an ever better understanding of the universe.

Also, even granted we can only speak of what appears to the mind, if those appearances do not in some way reflect an external reality, then all we are is minds floating in the solipsism of subjective experience. If, for example, one cannot say that the theory of gravity tells us something about the reasons why actual objects move toward the center of the earth, then some could claim that their experience tells them differently. A Science not grounded in the way the world would devolve into a set of divergent opinions all equally valid. Those opinions that would come to be taken as dominant (e.g.: “gravity is about smaller objects being forced toward larger objects) would be matters of opinion polls among scientists (as Kuhn suggests), not about a correct or incorrect understanding of the way things are.

Moreover, realists insist that taking the existence of the natural world as a given only serves to force scientists to take theories about the world more seriously. To suggest that science does not get us closer to the real world would be to suggest that all of the successes of theory and technology could only be understood, as Hilary Putnam has suggested, as miraculous.

The most powerful intuition motivating realism is an old idea, commonly referred to in recent discussions as the “miracle argument” or “no miracles argument”, after Putnam’s (1975a: 73) claim that realism “is the only philosophy that doesn’t make the success of science a miracle”. The argument begins with the widely accepted premise that our best theories are extraordinarily successful: they facilitate empirical predictions, retrodictions, and explanations of the subject matters of scientific investigation, often marked by astounding accuracy and intricate causal manipulations of the relevant phenomena. What explains this success? One explanation, favored by realists, is that our best theories are true (or approximately true, or correctly describe a mind-independent world of entities, laws, etc.). Indeed, if these theories were far from the truth, so the argument goes, the fact that they are so successful would be miraculous. And given the choice between a straightforward explanation of success and a miraculous explanation, clearly one should prefer the non-miraculous explanation, viz. that our best theories are approximately true (etc.)  (Chakravartty, Anjan, “Scientific Realism”, The Stanford Encyclopedia of Philosophy (Summer 2017 Edition), Edward N. Zalta (ed.), URL = <https://plato.stanford.edu/archives/sum2017/entries/scientific-realism/>.)

Also, realists argue the fact that science is so good at giving us not just theories but actual technologies for manipulating the world indicates that the theories we use to form those technologies are at least partially grounded in the material world upon which we use such technologies. The theory of optics, for example, is not just a current fad, for it is used to build eyeglasses and telescopes which help us gain not just a better appreciation of the mind, but of the actual world the mind is perceiving.

So, which approach is right?

Your answer will likely depend on how comfortable you are with ambiguity. Those who need to feel certain about the claims of science are more likely to fall into the realist camp, while those who are comfortable with ambiguity and a more fluctuating understanding of the world are likely to connect better with the anti-realist position. Where do you belong? Which approach to scientific knowledge makes the most sense to you?

Strengths and Weaknesses of Scientific Realism and Anti-Realism

Scientific Realism:
  • Aligns with commonsense scientific attitudes that theories describe reality.
  • Best explains the success of theories if they latch onto real unobservable structures.
  • Provides grounds for inductive optimism about present theories being true.
  • Gives a unified explanation of reference and predictive success of mature theories.

On the other hand, Realism:

  • Ignores how istory shows even successful theories have been proven radically false (e.g., phlogiston).
  • Runs the risk of confusing empirical adequacy with establishing truth of theoretical entities.
  1. Avoids realsim’s “miracle argument” that insists theoretical success be grounded in truth.
  2. Is less threatened empirically by anomalies and theory change.

On the other hand, it:

  • Cannot explain the instrumental success and predictive power of theories.
  • Risks very negative skeptical conclusions about scientific progress.
  • Conflicts with a scientific commitment to seek truths, not just empirically adequate models.
  • Makes it harder to motivate scientific endeavor without aiming at all for truth.

So both stances illuminate aspects of science but also face challenges in adequately reconciling scientific realism with theory dynamism over history. Integrating positions remains an ongoing project in philosophy of science.


Works Cited

Chakravartty, Anjan. “Scientific Realism.” Stanford Encyclopedia of Philosophy, Stanford University, 12 June 2017, https://plato.stanford.edu/archives/sum2017/entries/scientific-realism/.


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PPSC PHI 1011: The Philosopher's Quest by Daniel G. Shaw, Ph.D. is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.

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