Indeterminists

Indeterminists are proponents of indeterminism, the view that not every event is causally determined by preceding conditions. In philosophy, indeterminism is often discussed in the context of free will, where libertarian positions hold that some human actions are not determined by prior states and that genuine alternatives can be chosen. In physics, indeterminism refers to the apparent randomness of fundamental processes, most prominently in quantum mechanics, where events such as particle decays or measurement outcomes are described by probabilities rather than certainties. Many indeterminists distinguish between metaphysical indeterminism (there are events with no determinate cause) and practical or epistemic indeterminism (our predictive limitations do not imply that events are not caused in principle).

Historical notes include William James as a prominent defender of indeterminism in the philosophy of free will, arguing that free actions are real and not reducible to deterministic laws. In science, the mid-20th century saw quantum theorists such as Niels Bohr and Werner Heisenberg articulating a probabilistic framework for microphysical phenomena, which supporters cite as evidence of fundamental indeterminism. Critics—ranging from hard determinists to some scientists—argue that indeterminism may reflect gaps in knowledge or our models rather than a feature of reality. Some philosophers pursue a middle ground, suggesting determinism and chance operate at different levels of description or in different domains.

Today, indeterminists are situated within broader debates on determinism, free will, and the nature of scientific explanation. The term covers advocates of metaphysical indeterminism as well as those who emphasize quantum indeterminacy as a core aspect of the physical world, while others interpret probabilistic laws as effective constraints rather than fundamental ones. The topic continues to engage discussions of causation, luck, and responsibility.