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"It’s often assumed that physics and philosophy
are at opposite ends of the academic spectrum." notes Olivia Goldhill, Weekend writer at Quartz.
In fact, they’re close—so
close that they can overlap, with professors sometimes switching
between the two fields as they work to advance our understanding of
highly abstract subjects in theoretical physics.
Photo: Richard Dawid |
The criteria for establishing a theory, he
discovered, is not in itself subject to scientific enquiry. “They’re
considered background assumptions,” says Dawid. “It’s a question that’s
driven by physics but it’s a philosophical question.”
Physicists have long relied on a notion advanced
by philosopher Karl Popper, that a theory is scientifically valid if it
is falsifiable. But in recent years, many serious physicists seem to
have abandoned this model. String theory, for example, is one of the
most exciting ideas in modern physics. But it’s not testable—so how can
physicists be confident that it’s sound?
String
theory is at the crux of physics, as it links quantum mechanics with
Albert Einstein’s theory of relativity.
The theory argues that subatomic
particles are tiny, one-dimensional strings, rather than
zero-dimensional points, and are constantly vibrating. It’s thought that
at least 10 dimensions are curled up within the strings—but the
particles themselves are too small to be detected, let alone these extra
dimensions.
“String theory is not a fully developed theory,”
Dawid tells Quartz. “Some predictions string theory may give cannot be
calculated. It’s not accessible by present-day experiments or
experiments in the foreseeable future.
So what can we do with a theory
of that kind? We don’t want to live with a theory for 50 years and have
no clue whether it’s viable or not.”
The implausibility of testing string theory not
just now, but for decades to come, is a new problem for physics.
Although Einstein never conducted a single experiment, he put forward
his theory in 1915 and, by 1919, experiments found evidence to support
one of his key predictions, that a gravitational field causes light to
bend.
In cases where empirical evidence is unavailable, Dawid has identified three reasons why people believe in the veracity of the theoretical physics model; none of them are particularly strong by themselves but, in conjunction, he believes that they present strong grounding for trusting an un-provable theory.
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Source: Quartz