Science & Metaphysics, Then and Now

Note to students: As I mentioned in class, this is written more in the form of a handout for you. Your own summaries might benefit from being a bit more prose-y, as my first post and Farhan’s post were. Additionally, the discussion questions here are simple: there are a battery of arguments. As you read through them, ask yourself, “Do I accept these arguments? If not, which premise do I reject?”

Main Objective: Chakravartty seeks to refute the claim that some conceptions of scientific ontology require no metaphysical inferences. More positively: all conceptions of scientific ontology require metaphysical inferences.

  1. What are metaphysical inferences?

Metaphysical inferences are a species of Inference to the Best Explanation (IBE). This inference pattern is typically represented inductively:

            P is a fact in need of explanation.

            Q is the best explanation of P.[probably]


Roughly, an explanation best explains a phenomenon if and only if it optimizes the following kinds of criteria: simplicity, internal consistency, coherence with already-established science, scope, and unification.

Unlike other IBE’s, metaphysical inferences have pronounced a priori dimensions. Chakravartty provides three indications of what he means by this (35):

  • The explanatory hypothesis, Q, is the product of conceptual analysis.
  • The explanatory hypothesis, Q, describes a state of affairs that cannot be observed through the use of the unaided human senses.
  • The criteria that make one explanation better than another are defined and weighted by one’s intuitions.

Philosophers are likely to disagree about whether a particular IBE counts as a metaphysical inference, owing to the following sticking points: How strictly is “a priori” being defined?

  • For instance, if its antonyms, “a posteriori”or “empirical”, are restricted to claims that are knowable by the unaided human senses, then metaphysical inferences are legion.
  • However, there are more liberal notions of “a posteriori” that include any claims that are:
    • “Sensitive to” observation or
    • Knowable via the outputs of instruments such as microscopes and telescopes.

This more liberal notion of “a posteriori” will have a more restricted set of IBEs as metaphysical inferences.

2. Is Science Inherently Metaphysical?

Because science emerged from philosophy and theology, there is no doubt that earlier science is fraught with metaphysical inferences. However, what of contemporary science? Chakravartty looks at the arguments for and against.

2.1. Anti-Metaphysics: Empiricism

E1.       If some metaphysical inferences are sound, then we should accept some claims that posit unobservable entities.

E2.       We should not accept any claims that posit unobservable entities.

E3.       Therefore, no metaphysical inferences are sound.

2.1.1. Chakravartty’s “Zombie Argument” against E2

Z1.       If empiricism is true, then we should believe that science aims only at knowledge of the observable.

Z2.       Aims are unobservable.

Z3.       Therefore, if empiricism is true, then we should believe some claims that posit unobservable entities.

In other words, if empiricism is true, then E2 is false and the empiricists’ ban on metaphysical inferences is unsupported.

2.1.2. Chakravartty’s “Empirical Metaphysics Argument” (55-57)

EM1.   If empiricism is true, then observable entities must be distinguishable from both unobservable entities and “observable non-entities” (such as hallucinations, optical illusions, etc.)

EM2.   In at least some cases, distinguishing observable entities from unobservable entities and observable non-entities requires sound metaphysical inferences.

EM3.   Therefore, if empiricism is true, then at least some metaphysical inferences are sound.

2.2. Pro-Metaphysics

M1.      If successful science makes metaphysical assumptions, then some metaphysical inferences are sound.

M2.      Successful science makes metaphysical assumptions.

M3.      Therefore, some metaphysical inferences are sound.

2.2.1. Chakravartty’s “Reinterpretation Argument” against M2

R1.       If any putatively metaphysical assumption can be reinterpreted as an empirical assumption, then successful science need not make metaphysical assumptions.

R2.       Any putatively metaphysical assumption can be reinterpreted as an empirical assumption.

not-M2.   Therefore, successful science need not make metaphysical assumptions.[2]

2.3. Some Thoughts…

While it is historically accurate to describe empiricists as subscribing to a thin notion of the “empirical,” it is not clear why this is a necessary aspect of empiricism.

Furthermore, many empirical claims do not need to be justified via IBE of any sort. Presumably, they can be justified by observation.

If we combine these two points, then a liberal notion of the empirical provides a stronger anti-metaphysical argument than the one presented in §2.1: lots of things are observable and many of them can be known without any appeal to IBE. The remaining question would be if those that can only be known by IBEs are metaphysical inferences.

3. Epistemic Stances Regarding Scientific Ontology

Chakravartty restates some of his core ideas about stances, but emphasizes a few things that were understated in Chakravartty (2018):

  • Stances are non-propositional.
    • Propositions can be true or false and can be believed. Stances are neither. Instead of being believed, stances can be “adopted.”
  • They are orientations, clusters of attitudes, commitments, and strategies “relevant to the production of allegedly factual beliefs.” (p. 47; This seems a bit broader than an epistemic policy, but perhaps not.)
  • They can coexist with each other:

Where someone adopting the metaphysical stance may be tempted to affirm certain propositions regarding unobservable objects, events, processes, and properties, the holder of the empiricist stance does not deny such claims. Rather, the empiricist simply has no beliefs at all concerning such propositions… In this way the latter’s scientific ontology may be a subset of the former’s… (50)

4. “Metaphysical inference” versus “metaphysical inference”

Consider two IBEs:

Numbers IBE
The applicability of mathematics to science is a fact in need of explanation.
Numbers’ existence best explains why mathematics is applicable to science. [probably]
Numbers exist.
Gravity IBE
That apples fall is a fact in need of explanation.  
Gravity’s existence best explains why apples fall. [probably]
Gravity exists.

While most philosophers would agree that the “Numbers IBE” is a metaphysical inference, they might well disagree about whether the “Gravity IBE” is a metaphysical inference. Those who claim that Gravity IBE is non-metaphysical might claim that, at most, it is a metaphysical inference, but unlike the Numbers IBE, it is not a Metaphysical inference.

One might think that once we can pinpoint the “objective boundary” between little-m and Big-M metaphysical inferences, we can resolve some debates about scientific ontology. Chakravartty disagrees:

There is no boundary. Rather, there is something like a continuum ranging from lesser to greater magnitudes of metaphysical inference, and disagreement regarding which parts of this continuum are epistemically solid enough to serve as a basis for scientific ontology” (52).

5. Metaphysics without Scientific Ontology?

Most “professional” metaphysicians are not philosophers of science. (They are frequently called “analytic metaphysicians.”) They see themselves as doing something: (a) more “general” or “fundamental” than scientific ontology—but they also see what they’re doing as: (b) independent of scientific ontology. Chakravartty argues that these two claims are in tension.

            Specifically, if metaphysics is more general/fundamental, then it must show that it can subsume more specific/derivative scientific claims under its framework. However, this means that it depends on scientific ontology.

Chakravartty, Anjan. 2018. “Realism, Antirealism, Epistemic Stances, and Voluntarism.” In The Routledge Handbook of Scientific Realism, edited by Juha Saatsi, 225-236. Routledge.

[1] However, it can also be represented deductively:

It is rational to believe the best explanation of a fact in need of explanation.

P is a fact in need of explanation.

Q is the best explanation of P.

Therefore, it is rational to believe that Q.

Indeed, this might help us to more clearly see where stances come in—the “rational-to-believe parameter.”

[2] Note the switch to “need not” in this claim from the implication that successful science “(actually) makes” metaphysical inferences in the original pro-metaphysics argument.

1 thought on “Science & Metaphysics, Then and Now

  1. Nam Nguyen

    When reading through the section about metaphysics (2.1), I had a question about how concepts such as dark matter would interact with the arguments. As I understand it, dark matter is an unobserved substance. If this would count as an unobservable entity, and from my interpretation it should, then our modern understanding of science would posit unobservable entities. I am unsure about how this would interact with
    E1. (If some metaphysical inferences are sound, then we should accept some claims that posit unobservable entities) as I have a gap in understanding as to how scientists have come to the conclusion that dark matter exists in the universe. However, given that they do, it seems that we already accept some claims that posit unobservable entities.
    I also had a question in regards to Chakravartty’s “Reinterpretation Argument” against M2. In particular, I was unsure about why this argument doesn’t work in the opposite direction. If we do believe that any putatively metaphysical assumption can be reinterpreted as an empirical assumption, then it seems to be that we believe that any putatively metaphysical assumption can be an empirical assumption. If this is true, then from my understanding, some empirical assumptions are reinterpretations of metaphysical assumptions. And if some empirical assumptions can be reinterpreted as metaphysical assumptions, doesn’t that mean that successful science, when utilizing those specific empirical assumptions, makes metaphysical assumptions (or at least assumptions that can be reinterpreted to be metaphysical assumptions)?

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