Thales of Miletus is generally credited with being “the first philosopher in the Greek tradition [and] as the first individual in Western civilization known to have entertained and engaged in scientific philosophy” (Wikipedia). Less formally, he’s known as the ancient Greek who thought everything is made of water.
But that wasn’t a crazy idea at the time:
Thales [c. 624 – c. 546 BC] is recognized for breaking from the use of mythology to explain the world and the universe, and instead explaining natural objects and phenomena by theories and hypothesis, i.e. science. Almost all the other Pre-Socratic philosophers followed him in explaining nature as deriving from a unity of everything based on the existence of a single ultimate substance, instead of using mythological explanations. Aristotle reported Thales’ hypothesis that the originating principle of nature and the nature of matter was a single material: water (Wikipedia).
Jumping forward around 2,500 years, we’re still trying to figure out what everything is made of. If you’d asked me a few days ago, and given me a few seconds to think about it, I’d probably have said everything is made of very tiny particles like quarks and photons:
Fortunately, however, the scales have been lifted from my eyes. All it took was watching a lecture by a physicist named David Tong. It’s called “Quantum Fields: The Real Building Blocks of the Universe”. Here’s how he explains the situation on his University of Cambridge webpage:
We learn in school that the basic building blocks of matter are particles. In fact, we often continue to teach this in universities where we explain that quarks and electrons form the lego-bricks from which all matter is made.
But this statement hides a deeper truth. According to our best laws of physics, the fundamental building blocks of Nature are not discrete particles at all. Instead they are continuous fluid-like substances, spread throughout all of space. We call these objects fields.
The most familiar examples of fields are the electric and magnetic field. The ripples in these fields give rise to what we call light or, more generally, electromagnetic waves. The field [relating to a magnet is shown here].
From Fields to Particles
If you look closely enough at electromagnetic waves, you’ll find that they are made out of particles called photons. The ripples of the electric and magnetic fields get turned into particles when we include the effects of quantum mechanics.
But this same process is at play for all other particles that we know of. There exists, spread thinly throughout space, something called an electron field. Ripples of the electron field get tied up into a bundle of energy by quantum mechanics. And this bundle of energy is what we call an electron. Similarly, there is a quark field, and a gluon field, and Higgs boson field. Every particle your body — indeed, every particle in the Universe — is a tiny ripple of the underlying field, moulded into a particle by the machinery of quantum mechanics.
These fields fill the universe, even what seems to be empty space. All of the particles the physicists have identified are manifestations of these fields. In some sense, apparently, so are we.
Prof. Tong gave his lecture at the Royal Institution in London in November. It’s an hour-long introduction to Quantum Field Theory for the general public. He’s an entertaining speaker and, as an added bonus, he looks and sounds a lot like the comedian John Oliver.
If you want to jump ahead a little, it’s about nine minutes in when he announces that:
The best theories we have tell us that the fundamental building blocks of nature are not particles but something much more nebulous and abstract. The fundamental building blocks of nature are fluid-like substances which are spread throughout the entire universe and ripple in strange and interesting ways. That’s the fundamental reality in which we live. These fluid-like substances, we have a name for, we call them “fields”.
Have fun. After this, you may never see the world in the same way.
(Hmm, notice how I didn’t mention You Know Who once? This should not suggest that anything is back to normal yet. Far from it.)