Interference – From physical to political

Hard and soft science

Do you remember back in high school when your physics teacher told you that he or she taught a “hard” science?¹ In case you are unfamiliar with the terms “hard” and “soft” science, I’ll repeat this little Wikipedia snippet:

Hard science and soft science are colloquial terms used to compare scientific fields on the basis of perceived methodological rigor, exactitude, and objectivity. Roughly speaking, the natural sciences are considered “hard”, whereas the social sciences are usually described as “soft”.

At first glance, physics does seem to score pretty high on the “hard” list compared to, say, questionable sciences like, say psychology, sociology, and religious studies. But it still fails on one big point. What’s that?

In a word, objectivity.

This shortcoming – or perhaps simply unavoidable reality – becomes clear when we look at the idea of interference.

Interference explained

In the world of physics, interference can be observed when two or more waves of energy interact to create a disturbance in the same medium.

Constructive interference can be observed when two or more wave ‘crests’ meet, displaying a positive amplitude.

Destructive interference can be observed when two or more ‘troughs’ meet, exhibiting a negative amplitude.

“Plate 3. “Interference.” Light, a course of experimental optics, chiefly with the lantern. 1892. ” | Pinterest

In everyday life, interference patterns can be seen by anyone throwing two or more stones into a lake and observing their interacting ripples.

Thomas Young (1773–1829) demonstrated with the double-slit experiment that light exhibits interference patterns, which lead to his wave theory of light.

However, under different experimental conditions, light also behaves like a particle, usually understood as a photon.

This puzzle lead to the idea of a particle-wave duality that refers not just to light but, as later theorized, to all objects.

The idea of duality originated in a debate over the nature of light and matter that dates back to the 17th century, when competing theories of light were proposed by Christiaan Huygens and Isaac Newton: light was thought either to consist of waves (Huygens) or of particles (Newton). Through the work of Max Planck, Albert Einstein, Louis de Broglie, Arthur Compton, Niels Bohr, and many others, current scientific theory holds that all particles also have a wave nature (and vice versa).[1] This phenomenon has been verified not only for elementary particles, but also for compound particles like atoms and even molecules. In fact, according to traditional formulations of non-relativistic quantum mechanics, wave–particle duality applies to all objects, even macroscopic ones; but because of their small wavelengths, the wave properties of macroscopic objects cannot be detected.²

Oops. Suddenly our “hard” science of physics begins to look a little soft and fuzzy.


Well, depending on how we observe light, it can behave as a wave or as a particle. In other words, the way we set up our experiment determines the observed outcome.

So much for objectivity.


This conundrum has led many popular thinkers to talk about science as just another human activity.

Physics, for all its practical successes in helping to develop technological marvels, is still based on human theories about our world. As Jacob Bronowski says in the BBC video series, The Ascent of Man, science depends on and, in turn, recreates a human representation of reality, not unlike a work of art.³

We can never know the actual thing studied. We can only know how it appears or leaves hints or traces of its appearance as we observe through the naked eye, the Hubble Space Telescope, or an electron microscope.

The holistic thinker, Peter Russell put it this way: We should never confuse the map consisting of scientific concepts and theories with the thing mapped, which turns out to be somewhat elusive and mysterious.

If this is true for the “hard” sciences, how much more for the “soft” sciences?

This obvious truth does seem to make science appear like something of religion whenever naive people mutter the latest scientific buzzwords or studies without really understanding just how entirely relative those buzzwords and studies are.

Even worse, sometimes clever, twisted people with a hidden agenda – say, for instance, a Soviet-era spy – use scientific-sounding talk for their nefarious purposes even when they know full well that they are conveying sheer nonsense.

Basically, they gamble that everyday people will be fooled because fooling people is their modus operandi.

¹ I was blessed with an excellent physics teacher, Joseph Fox, who humorously admitted that the  Bohr model of the atom was “wrong.” Mr. Fox grew up on a farm but ultimately chose math over milking cows. He came to North Toronto Collegiate from the USA, where he had developed cathode ray tubes for RCA.

² Source:…particle_duality (2011 entry – The 2022 entry is a bit more detailed).

³ The series also appears in book form, with text matching the TV script. The Ascent of Man: Boston/Toronto, Little, Brown and Company, 1973, pp. 321-367.


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