If a theory explains the physical world well, does that mean the theory's unobservable aspects exist?
For example, does the success of nuclear science mean that sub atomic particles are real entities and not just mathematical abstractions that are useful?
Example 1: The "iota", an imaginary number (square root of minus one) is indispensable in motion equations that are highly successful in describing the motion of real objects - so it is indispensable in mechanical engineering. It is indispensable in quantum electrodynamics, as well as in many other aspects of electrical engineering. Even aerospace, civil..long list.
Example 2: The "absolute zero" too is imaginary. There is no quantity in the real world that is ever "absolute zero". But can modern machines exist without the concept of "absolute zero"? No.
i.e., imaginary concepts are indispensable parts of theories, equations, as well as practically useful engineering equations. So 'protons', 'electrons' etc. may be just neat little mathematical constructs like the "Iota" and the "Zero". Laboratories do not "see" sub atomic particles like we see everyday objects. They see data, numbers, and they then fit the data to theoretical models. It has worked till now. It may not, tomorrow.
A scientific realist would argue that science must derive some ontological support for atoms from the outstanding phenomenological success of all the theories using them.
This is obviously not correct. And this is where the Constructive Empiricist steps in...
(Abstracted from the Stanford University Online Library)
Copyright © 2014 by The Metaphysics Research Lab, Stanford University.
Constructive empiricism is the version of scientific anti-realism promulgated by Bas van Fraassen in his famous book The Scientific Image (1980).
Van Fraassen defines the view as follows:
Science aims to give us theories which are empirically adequate; and acceptance of a theory involves as belief only that it is empirically adequate. (1980, 12)
A theory is empirically adequate exactly if what it says about the observable things and events in the world is true — exactly if it ‘saves the phenomena.’ (van Fraassen 1980, 12)
To understand the above account, one needs first to appreciate the difference between the syntactic view of scientific theories and van Fraassen's preferred semantic view of scientific theories.
On the syntactic view, a theory is given by an enumeration of theorems, expressed in some one particular language.
In contrast, on the semantic view, a theory is given by the specification of a class of structures (describable in various languages) that are the theory's models (the determinate structures of which the theory holds true).
As van Fraassen says,
To present a theory is to specify a family of structures, its models; and secondly, to specify certain parts of those models (the empirical substructures) as candidates for the direct representation of observable phenomena. (1980, 64)
A theory is empirically adequate, then, if appearances — “the structures which can be described in experimental and measurement reports” (1980, 64) — are isomorphic to the empirical substructures of some model of the theory.
Roughly speaking, the theory is empirically adequate if the observable phenomena can “find a home” within the structures described by the theory — that is to say, the observable phenomena can be “embedded” in the theory.
|The constructive empiricist rejects arguments that suggest that one is rationally obligated to believe in the truth of a theory, given that one believes in the empirical adequacy of the theory.|
For this epistemological argument to work, the distinction between empirical adequacy and truth has to be well-founded.
Constructive empiricism is a view which stands in contrast to the type of scientific realism that claims the following:
Science aims to give us, in its theories, a literally true story of what the world is like; and acceptance of a scientific theory involves the belief that it is true. (van Fraassen 1980, 8)
In contrast, the constructive empiricist holds that science aims at truth about observable aspects of the world, but that science does not aim at truth about unobservable aspects.
Acceptance of a theory, according to constructive empiricism, correspondingly differs from acceptance of a theory on the scientific realist view: the constructive empiricist holds that as far as belief is concerned, acceptance of a scientific theory involves only the belief that the theory is empirically adequate.
Dr. Michela Massimi is a Ph.D from the London School of Economics, and a senior lecturer of philosophy at the University of Edinburgh.
In the following video, she explains Constructive Empiricism:
Terms used by Dr. Massimi:
1. "Scientific realism":
Is a positive epistemic attitude towards the content of our best theories and models, recommending belief in both observable and unobservable aspects of the world described by the sciences.
2. "Scientific Anti-realism":
In philosophy of science, anti-realism applies chiefly to claims about the non-reality of "unobservable" entities such as electrons, which are not detectable with human senses.
Relating to knowledge or to the degree of its validation.
The philosophical study of the nature of being, becoming, existence, or reality, as well as the basic categories of being and their relations.
5. "Empirical Adequacy":
Roughly speaking, if a theory works in practical life, it is called empirically adequate.
6. "Semantic aspect":
Semantics is the study of meaning.
7. "Syntactic aspect":
Syntax, or the study of structure.