Philosophy of physics

The philosophy of physics can be seen as a branch of philosophy of science or the philosophy of nature, and thus the ontology to be understood and deals with philosophical issues raised by the theories of modern physics, as well as conceptual foundations of these theories.

• 4.1 determinism

• 5.1 Textbooks and manuals
• 5.2 interpretations of physical theories

Problems of interpretation of physical theories

To the fields of philosophy of physics, the interpretation of physical theories heard in terms of their ontological presuppositions or implications: If a particular physical theory our world describes well, it follows, at least for epistemological realists that these theories provide information about the structure of reality. Even the interpretation and rational reconstruction of the classical ( Newtonian ) particle mechanics throws this into problems. Even more complicated are the problems in the interpretation of statistical physics, quantum mechanics, relativity theory and quantum field theory.

Thermodynamics

For example, several attempts to return the directionality of time on the directionality of physical processes. Because not all physical phenomena are time-reversal invariant (ie they reigning equations lead to the process in the reverse direction, as can be easily modeled by reversing the sign of the time parameter ). The thermodynamics for example, calls for an increase in entropy over time. However, since the thermodynamic processes are ultimately realized by the smallest particles, which are actually for the zeitumkehrinvarianten laws of classical particle mechanics, the relationship between the two theories is another explanation. Already Boltzmann has sought to find a solution to this problem in the 19th century. Today's theorists are mostly agree that his statement is wrong, but this error diagnose partially different.

Relativity theory

For the philosophy of time, the special theory of relativity raises problems. Because the demanded relativity of simultaneity is at odds with certain metaphysical theories about the nature of causality and modality ( for example, a modallogisch considered dynamic universe splits off with them unrealized possibilities, as suggested by Storrs McCall, Michael Tooley and other metaphysicians ).

Quantum mechanics

In the case of quantum theory is a major problem of interpretation of experiments, such as the time evolution of the state values ​​behaves to the measurement process. The former fact is deterministic, the results of the latter are only stochastically predictable. Usually one says that (in most cases ) the actual system state is a so-called superposition state, which is reduced in the measurement to a unique state, with a probability, which can be specified by the Born rule. The scientific realist must now explain what corresponds in reality such a superposed state. To this end, there are a variety of possible answers. Alternatively, different anti-realist interpretations were offered. It is also controversial, how exactly can be characterized in physical or ontological language that makes a measurement process (see the Quick Reference Guide in the main article quantum mechanics, the more detailed presentation in interpretations of quantum mechanics and the discussion in related articles such as Wigner's friend).

Furthermore seem more realistic interpretations that have been discussed in particular in the debate on the EPR effect, incompatible with classical views on the ( lokalursächliche ) nature of causality.

Metaphysical problems

Since especially the theory of general relativity is the basis for modern cosmological models, the philosophy of space-time and relativity touched in some areas strongly with the cosmology.

This interpretation problems usually are closely related to the interest in metaphysical questions concerning the nature of space, time and causality, as well as the constituents of reality. For the latter issue, the controversy about it is fundamental, whether theoretical terms, ie the words that go in the center of the formulation of a theory, such as " atom" associated per se with the condition that corresponds to them something in reality. Many epistemological realists call this anti- realists, in particular the already classic Operationalism (such as developed him Percy Williams Bridgman ) deny it. The modern epistemological realist seems but then to have to absorb not only atoms but also quantum fields and in his ontology; Also, he ( apparent ) transformations of "matter " in " energy " and vice versa explain.

Epistemological problems

As quantum mechanics, especially in some anti-realist interpretations, also raises the special theory of relativity on epistemological questions.

General epistemological problems

Determinism

Relatively independent of the problems of interpretation of physical theories includes the matter to the general nature of physical laws in the philosophy of physics. Since modern physics in some areas may take only statistical statements, in particular the regional or general application of determinism is controversial. Partial try some philosophers, this discussion with questions about the freedom of the will (partly also of the divine foreknowledge ) to join. In many cases, appropriate rescue attempts by the free will of philosophers of science to be viewed critically.