Question:
Can we know for certain that the world exists independent of our experience? I've seen toddlers assume that they know the answer to this question when they cover their eyes to "hide." A more dangerous example of this instinct to deny the existence of things we can't see can be found in the history of medicine. Before doctors accepted the existence of bacteria, they would go straight from dissected cadavers into the delivery room to welcome new babies into the world-without washing their hands! Even though new mothers kept dying puerperal fever (because of bacteria from rotting corpses making its way into the mother's birth canal), it took a very long time for doctors to embrace the idea that bacteria even existed and even longer to believe that hand washing could save lives.
If it does exist, can we actually describe that world through science (or other forms of knowledge)? Given the crazy weather we've had this year, the first example that pops into my mind that grapples with this question is the issue of global warming. Science has rather clearly asserted that the planet is warming, and this warming is exacerbated by our emissions of greenhouse gases. However, we still see headlines wondering if global warming is a hoax or assertions that it has nothing to do with human activity. In this case, there is a significant part of the population that believes that science has not accurately informed us on this issue.
These are age-old conundrums, which as been addressed by philosophers since before Plato. Scientific realism asserts that the world does exist and science can indeed accurately model it.
Scientific Realism
Scientific realism identifies the position, generally complementary to but not identical with naturalism, that the physical world described by science exists, even if our understanding of it is mediated through our senses, tools, and experiences. It takes a variety of forms, but all versions involve some level of commitment to three propositions (Chakravartty):
The world exists outside of the mind that perceives it.
Scientific claims are literal claims about reality.
Scientific theories are knowledge of the real world. While a specific theory may prove to be true or false, its truth value is determined by its relationship to the independently existing real world.
Thus, to use the example from our textbook, electrons have always existed, even though the scientific concept and definition of the electron is of relatively recent vintage. The planets have always revolved around the sun, even though we did not recognize this fact until Copernicus developed the heliocentric model of the solar system. Science, while it may always be improved, does provide us with a reasonable description and understanding of an independent reality.
Why do scientific realists support these propositions? Three primary arguments justify realism:
The No-Miracles Argument. The success of science in predicting outcomes would be extraordinarily unlikely if it were not connected to an independent reality. The most famous formulation of this claims comes from Hilary Putnam: "The positive argument for realism is that it is the only philosophy that does not make the success of science a miracle" (qtd in Cruse 3). You may view a brief video explaining this argument here.
The Corroboration Argument. Because the reality described by science has been described in multiple, theoretically independent ways, the independent existence of reality has been confirmed.
The Selectivity Argument. Given that falsifiability is a key component of scientific reasoning, most scientific theories have been or will be proven false. However, one may identify the theories that are closest to describing a genuine knowledge of reality based on their explanatory and predictive power.
Anti-Realist Criticisms
While scientific realism seems common sense, it has been challenged in many ways. Consider, for example, a famous thought experiment posed by quantum physics. Schrödinger''s Cat illustrates a basic principle of quantum mechanics, derived from Heisenberg''s Uncertainty Principle, that the act of observation itself determines the outcome. John Lienhard explains the problem for scientific realism:
But in the end we have to look inside the box to learn whether the cat is alive or dead. So it is that the observer determines the the truth. This makes an odd commentary on objective science. We''re left to wonder if scientists aren''t far more deeply interwoven with the world they observe than they would like to be.
If the act of observation in and of itself affects the outcome of an experiment, how can we endorse or accept the idea that an independent reality exists?
The philosophical objections to scientific realism take several forms:
The Underdetermination of Theory by Evidence (the Duhem-Quine Thesis). In most cases, the data examined by science can be explained using multiple theories. The choice of one theory over another therefore depends on something other than the reality the theory purports to describe. As Chakravatty puts it, "Every theory . . . has empirically equivalent rivals-that is, rivals that agree with respect to the observable, but differ with respect to the unobservable. This then serves as the basis of a sceptical argument regarding the truth of any particular theory the realist may wish to endorse."
Questioning Inference to the Best Explanation. Science generally favors the "best explanation" of the data, but the grounds of choosing what is "best" leave room to question the ability of science to provide genuine knowledge of reality. Occam''s Razor, or the Simplicity Principle, is often invoked to choose one theory over another, but there is no philosophical justification necessitating that the simpler theory must be more accurate than a more complicated theory. Nor is there a necessary connection between a theory being the "best" available, by any criteria, and it being a true description of any independent reality.
Pessimistic Induction. This argument is an inverse of the Selectivity Argument in favor of scientific realism. Because most theories in the history of science have been proven false, inductive reasoning from these specific instances to a general principle argues that scientific theories will generally prove to be false. Therefore, science can never expect to achieve an accurate representation of any reality that exists independently of our scientific explanations of what we currently believe that reality to be.
No Resolution in Sight
This week''s readings and discussion focus on a fundamental problem that reaches back to Plato and shows no signs of a final resolution. This lesson will close with a brief summary of two pragmatic ways to deal with this problem.
The first solution is to set aside the question as irrelevant. Outside the rather abstract debates of philosophers and late-night existential debates amongst friends, the ultimate existence of reality and whether or not it can be accurately determined by science does not matter much. What matters, in this view, is what van Fraassen terms the "empirical adequacy" of a given theory.
The second solution, rather than setting aside the problem of realism and anti-realism entirely, instead seeks a middle ground that provisionally accepts some of the arguments from both sides. The result is a kind of weak scientific realism, in which many of the critiques of anti-realism are acknowledged or accepted, but without abandoning the realistic position entirely. This position, though somewhat muddled in philosophical terms, may reflect how most non-philosophers resolve the issue.