1.0 On Generation & Corruption

An Introduction to the State of Today's Physics

In the past century, our understanding of physical reality advanced exponentially. We can now predict and quantify a wide variety of phenomena to a level of detail far beyond what lay in reach of previous generations. Our models employ sophisticated mathematical techniques that confound all but the most advanced practitioners. Our models work – they correctly predict and describe the results of the most ingenious experimental tests. Yet, the physical interpretation of our models often defies common sense. Does this conflict mean we may have been thinking about fundamental physics the wrong way?

Perhaps we should not expect common sense, based as it is on the world of everyday experience, to explain the most subtle workings underpinning reality. Perhaps we must discard our common sense in favor of a more pragmatic attitude: “shut up and calculate.” So long as the results of our model agree with experiment, does it truly matter that the fundamental theory on which we rely doesn’t make sense, at least for certain values of “sense?”

Some malcontents refuse to accept the wisdom of the scientific consensus, however. They attempt to look beyond and around the perfectly satisfactory mathematical theory, seeking a more intuitive solution – a better, more sensible story to describe how things work.

One such malcontent was Michael Faraday (1791–1867). The year was 1830. The mathematical theory Faraday questioned is instantaneous action at a distance. The remarkably intuitive solution he devised is called a “field.”

The prevailing notion in physics was that reality comprised point particles whose interactions followed mathematical laws that depend on the distance between the particles. After all, the great Isaac Newton (1643–1727) had demonstrated his Law of Universal Gravitation and, following in Newton’s footsteps, Charles Augustin de Coulomb (1736-1806), André Marie Ampère (1775–1836), and others discovered electric and magnetic forces took a similar form.

Action at a distance troubled Faraday. How can a body act where it is not? The complexity of calculating how charges and currents over here exert forces on charges and currents over there further defied his common-sense comprehension.

Instead, Faraday studied iron filings interacting with magnets. He imagined he was seeing “lines of force” filling the space around charges and currents, connecting the over here to the over there and providing a common-sense model of how electricity and magnetism work. He devised ingenious ways to capture the patterns of iron filings aligned under the influence of magnetic fields in hot wax. When cooled, Faraday’s technique preserved the magnetic field patterns for further study and for posterity. Figure 1.1 shows Faraday and one of his iron filings experiments.

Figure 1.1: Faraday (left) and patterns of iron filings around magnets (right) that inspired his conception of “lines of force” [[i]].

Students of physics know the rest of the story. Faraday used fields to discover induction – the physics behind electric motors and generators. James Clerk Maxwell (1831–1879) and his contemporaries built upon Faraday’s insight to develop electromagnetic theory, embodied in what we now call “Maxwell’s equations.” These equations underlie much of modern technology, from analog and digital electronics, to wireless communications, radar, geo-location, and much, much more.

In On Generation and Corruption, Aristotle (384–322 BC) discussed the science and philosophy of “coming to be” and “passing away.” Yet we still wrestle with the coming to be and passing away of scientific ideas, themselves.

Today, physics finds itself in a similar position as in the days of Faraday. We are in possession of even more sophisticated mathematical techniques. These tools have enormous power to predict the most subtle aspects of reality. Yet they often appear every bit as unreasonable as the notion that action takes place instantaneously across a distance with no intermediate mechanism or process. As in Faraday’s time, we must ask ourselves, have we been thinking about physics the wrong way?

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[i] Michael Faraday. Photograph. Credit: Wellcome Collection. CC BY and Results of Michael Faraday's iron filings experiment. Credit: Wellcome Collection. CC BY