AF Chalmers - What is this thing called Science?

Chapter 15 – Realism and anti-realism



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Chapter 15 – Realism and anti-realism

If Chalmers discussion is reliable (=accepted among philosophers), then science is based on a mixture of realism (a belief in that a world exists) and anti-realism (final “knowledge” of the world has not been found).


Realism, with respect to science, implies that science describes not just the observable world but also the world that lies behind the appearances.

Realism denotes a belief that a reality exists, independent of our interpretations about it.

Science denotes reports containing careful descriptions of observations and/or hypotheses based on them.

With respect to non-scientific hypotheses (that are not based on observations), the discussion about realism is interesting, but fruitless as shown during more than 2000 years.


Claims about the unobservable world must be hypothetical to the extent that they do transcend what can be firmly established on the basis of observation.

Unfortunately Chalmers does not define what he means by the term “unobservable”. It certainly should not mean parts of the world that we have no clues to at all.

Every statement about the directly observable and not directly observable world is a probability argument, i.e. it is not deductively inferred.

No statement about our perceived world represents “absolutely certain knowledge”.


Although the theoretical parts of those theories have been rejected … those parts of them that were based on observation have been retained.

Chalmers is touching why science demands carefully described observations, or why a hypothesis should be verified by such observations.


The realist position reflects the unthinking attitude of most scientists and non-scientists.

The term “unthinking” should be replaced by “experience proven”.


The anti-realist stresses the inconclusiveness of the evidence for the theoretical part of science.

Every hypothesis (theory) is basically founded on observations that only provide us with probability arguments. This opinion is a foundation within scientific methodology.

The statement that the evidence is “inconclusive” is correct because a hypothesis about our perceived reality can never be created using deductive arguments only.


Global antirealism denies we have access to reality in any way.

We are all global antirealists.

Due to the definition of the term “reality” (which would use a term similar to “absolutely certain knowledge”, see comment to p.xx) this is philosophically correct.

But neither can we claim that we do not know anything about the world as it is actually built, also such a statement claims that we have “knowledge”.


No knowledge can have any kind of privileged position as a characterization of the world because we lack the kind of access to the world that would serve to justify this.

The statement is philosophically correct because “knowledge” in the meaning of “absolutely certain knowledge” cannot be shown to exist. See comment to p.xx.

But carefully described observations about our perceived reality (science) yield a less uncertain opinion about this reality than other types of narratives.


According to the correspondence theory, a sentence is true if and only if it corresponds to the facts.

Because the term “fact” is dependent on the term “true”, this is a tautology that demonstrates the enormous need of definitions within philosophy (or conversely: Demonstrates benefits of lack of definitions if you want to express pretentious nonsense).


Tarski showed how the notion of truth can be built up from this starting point for all the sentences of the language.

Let us hope that he strictly defined his terms in a manner that his reasoning is in accordance with an epistemological basis (please note the irony).


A realist will typically claim that science aims at theories that are true of the world, both observable and unobservable, where truth is interpreted as the commonsense notion of correspondence to the facts.

A realist will probably claim the science aims at descriptions that are in accordance with our perceived world.

The term “truth” and “facts” are hopefully omitted.


The traditional debate … concerns the issue of whether scientific theories should be taken as candidates for the truth in an unrestricted sense, or whether they should be taken as making claims about the observable world only.

The phrase uses several undefined terms, which probably also is the reason for any debate within this area.


For instrumentalists theories are nothing more than useful instruments for helping us to correlate and predict the results of observation and experiment

If this is correct (=accepted among philosophers), instrumentalism is in accordance with opinions behind the scientific method.


Anti-realism seems to be the desire to restrict science to those claims that can be justified by scientific means, and so avoid unjustifiable speculation.

Theoretical parts of science do not qualify as securely established.

If this is correct (=accepted among philosophers), anti-realism is in accordance with opinions behind the scientific method.


The anti-realist presupposes that observations are securely established, but that theoretical knowledge cannot be securely established.

Observations are often more securely established as compared to hypotheses, because hypotheses often involve non-deductive inferences from observations. As an example see comment to p.41 about induction.



Various arguments based on not well-defined terms.




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