Friedel Weinert

Compendium of Quantum Physics

The role of operational quantum mechanics, quantum axiomatics and quantum structures in general is presented as a contribution to a compendium on quantum physics, its history and philosophy.

The Construction of Atom Models: Eliminative Inductivism and its Relation to Falsificationism

Falsificationism has dominated 20th century philosophy of science. It seemed to have eclipsed all forms of inductivism. Yet recent debates have revived a specific form of eliminative inductivism, the basic ideas of which go back to F. Bacon and J.S. Mill. These modern endorsements of eliminative inductivism claim to show that progressive problem solving is possible using induction, rather than falsification as a method of justification. But this common ground between falsificationism and eliminative inductivism has not led to a detailed investigation into the relationship, if any, which may exist between these two methodologies. This paper reviews several versions of eliminative inductivism, establishes a natural relation between eliminative inductivism and falsificationism, which derives from the distinction between models and theories, and carries out this investigation against a case study of the construction of atom models. The result of the investigation is that falsificationism is a form of eliminative inductivism in the limit of certain constraints.

The Duhem‐Quine thesis revisited

Abstract The Duhem‐Quine thesis is generally presented as the radical underdetermi‐ nation of a theory by experimental evidence. But there is a much‐neglected second aspect, i.e. the coherence or interrelatedness of the conceptual components of a theory. Although both Duhem and Quine recognised this aspect, they failed to see its consequences: it militates against the idea of radical underdetermination. Because scientific theories are coherent conceptual systems, empirical evidence penetrates, as it were, the periphery and allows the localisation of central, not just peripheral hypotheses. There is then no reason to deny the existence of crucial experiments. Both these ideas are denied in the Quine‐Duhem thesis. A discussion of the famous Stem‐Gerlach experiment and the role of fundamental physical constants shows, however, that localisation is not only possible but essential for the validity of scientific theories. Quines famous ‘latitude of choice’ turns out to be severely restricted.

Time and Cosmology

Running through the whole history of time reckoning is a deep connection between time and cosmology. It is essential for the measurement of time, since it provides periodic regularity. The early Greeks established the association of time with periodic regularity on a planetary scale. Regularity, however, is not a sufficient condition for the objective measurement of the passage of time. A further condition is needed: invariance, the importance of which came to the fore with the Special theory of relativity.

Einstein and the Laws of Physics

The purpose of this paper is to highlight the importance of constraints in the theory of relativity and, in particular, what philosophical work they do for Einsteins views on the laws of physics. Einstein presents a view of local structure laws which he characterizes as the most appropriate form of physical laws. Einstein was committed to a view of science, which presents a synthesis between rational and empirical elements as its hallmark. If scienti c constructs are free inventions of the human mind, as Einstein, held, the question arises how such rational constructs, including the symbolic formulation of the laws of physics, can represent physical reality. Representation in turn raises the question of realism. Einstein uses a number of constraints in the theory of relativity to show that by imposing constraints on the rational elements a certain t between theory and reality can be achieved. Fit is to be understood as satisfaction of constraint. His emphasis on reference frames in the STR and more general coordinate systems in the GTR, as well as his emphasis on the symmetries of the theory of relativity suggests that Einsteins realism is akin to a certain form of structural realism. His version of structural realism follows from the theory of relativity and is independent of any current philosophical debates about structural realism.

Einstein and Kant

The paper aims to explain and illustrate why Einstein and Kant, relativity and transcendental idealism, came to be discussed in one breath after the Special theory of relativity had emerged in 1905. There are essentially three points of contact between the theory of relativity and Kants objective idealism. The Special theory makes contact with Kantian views of time; the General theory requires a non-Kantian view of geometry; but both relativity theories endorse a quasi-Kantian view of the nature of scientific knowledge. The paper shows that Einstein is a Kantian in his insistence on the synthesis of rationalism and empiricism, but not in the details of his physics.

The Role of Trust in Political Systems. A Philosophical Perspective

Abstract The paper analyzes the question of whether trust is an essential condition for the functioning of social and political systems; it approaches the issue from a philosophical perspective. Trust appears in both interpersonal relationships (interpersonal trust) and in societal and political institutions (social and political trust, respectively). In the political literature trust is sometimes characterized as ‘an expectation of continued value’. Although the same literature distinguishes social from political trust, the thesis advanced here is that, logically, all forms of trust must be characterized as an inductive generalization from past experience to future expectations of the continuation of some specifiable utilities (goods, services). As such, trust suffers from Humean reservations about inductive inferences. Trust as an expectation of the continued provision of utilities, on the institutional level, will be characterized as a first-order sort of trust. It can be disappointed without necessarily threatening the continuation of a given institution, especially if there is no alternative service provider. But trust as an expectation of the continued functioning of democratic mechanisms will be characterized as a second-order sort of trust. The paper will argue that the second-order kind of trust is essential for the functioning of democracies.

Loschmidt’s Demon: Reversibility and Irreversibility

What would happen to a volume of gas, which was left to expand in a sealed container without the interference of a demon? If a perfume bottle was placed in a sealed container and then opened, the molecules would spread throughout the available volume.

The Time-Reversal Invariance of Fundamental Laws

The time-reversal invariance of fundamental laws is one of the basic arguments not only for determinism, but also in favour of the afore-mentioned Block universe. The fundamental laws make no distinction between past, present and future and hence do not give rise to an arrow of time. It is an essential feature of many fundamental laws that they are time-reversal invariant.

The Function of Thought Experiments

The discussion so far has encountered a number of suggestions as to the function of thought experiments. Ernst Mach stressed the role of instinctive experience in thought experimentation, and placed thought experiments as the middle way between, in Francis Bacon’s analogy, the bee—the accumulation of facts—and the spider—the flight of pure thought.