Exploring an idea
Abstract it!
Good mathematicians do it a lot.
Theoretical physicists often make a point of it.
This matrix chart is a combination of Keith Devlin's four levels of abstraction and our concept of simple-complex / easy-difficult.  We will often use this chart to make points about specific issues—here we examine the difficulty encountered with the energy concept.

Some growth of scientific thinking — from infancy to science-see

What is energy?

<-- easy       This dimension is abstraction --->       difficult --->   (the human evolutionary path)

a few other critters
only humans
a stretch for us
beyond comprehension
even worms do it
even plants do it
(a bit)

















I'm hungry.
I'm tired.
I'm sleepy.
I eat.
I rest.
I sleep.


My (empty) plate could be full.

If I intone:
"oooooooomm abracad..."


"Energy": at work


 "Energy is the capacity to do work"

some text authors

 “...in physics today, we have no knowledge of what energy is...It is an abstract thing...”

Richard Feynman

Many of those who declare, "Energy is the capacity to do work," seem not to see why that cannot be.

Human knowledge begins  with perceptions and experiences.  Hunger and fatigue are strong feelings.  We strongly sense that something about food and rest are essential to staying alive.  Modern man sees something similar in the fuel he puts into his automobile and the electricity he powers his home with.

Self-preservation is here.

We look.  We see. We imagine.  We imagine alternatives to what we see, and sometimes those alternatives are nicer than what we see.  Sometimes the "nicer" is possible.  Sometimes it isn't.  If we consider that which isn't, is, we might get ourselves into trouble.  (But we might work on it to make the nicer real.)

Self-deception lurks here.
Once we define our terms carefully, we can communicate with others who may see parts of answers we don't see.

Patterns in the things we see sometimes allow us to predict what happens next.  Prediction makes for effective actions.

Community through communication

Modern science—that of the past several centuries—looks very little like the science of Aristotle. 

Abstract patterns lead us to the real power of modern science.

The energy of Aristotle, when seen with the eyes of science, will be seen to be fundamental to our need for abstract patterns.

Miracles become reality.

Feynman's discussion of "What is energy," in his The Feynman Lectures on Physics, is very different from most other authors' discussions of the same question.  Feynman was known as a "magician" because he saw things that others realized they would never have seen.

Mystery haunts us.

pattern perception
pattern blindness

desirability -- possibility
should be -- is
attractive -- possible
wish -- reality


pattern perception
pattern blindness

These two issues (pattern perception and logical imperative) and their opposites (pattern blindenss and self-deception) are central to the problems of pseudoscience.

pattern perception
pattern blindness

We want to develop these two concepts, and the language we use to discuss them, so that what we do is not so much discuss them, but rather demonstrate them.

pattern perception
pattern blindness

The energy discussion continues below -- but these two issues need to be a parallel consideration to the discussion of energy.

pattern perception
pattern blindness
Mid 19th Century
The first step to understanding energy was to recognize that many different variables go into making food or fuel useful--"for doing work."  Scientific "energy" got separated from many other things.
Late 19th Century
The statistical nature of "capacity for doing work" became thoroughly understood.
20th Century
Quantum Mechanics and Einstein's Relativity showed us some of the fabric of reality that is beyond our comprehension. "Energy" is seen to be the same thing as "mass" looked at in a different way.

To understand energy we must understand "random."

RANDOM DOTS Imagine that you are wandering in this forest of dots but can see only about as far as the average distance between dots. How could you become able to predict where the more distant dots are located?
o  o  o  o  o  o  o  o  o  o  o  o  o  o  o o  o  o  o  o  o  o  o  o  o  o  o  o  o  o o  o  o  o  o  o  o  o  o  o  o  o  o  o  o o  o  o  o  o  o  o  o  o  o  o  o  o  o  o o  o  o  o  o  o  o  o  o  o  o  o  o  o  o o  o  o  o  o  o  o  o  o  o  o  o  o  o  o o  o  o  o  o  o  o  o  o  o  o  o  o  o  o o  o  o  o  o  o  o  o  o  o  o  o  o  o  o UN-RANDOM DOTS You can think of many ways to describe this pattern so that you can tell someone unfamiliar with it what  it is. There are many mathematical ways to describe it, too.
NOT EXACTLY RANDOM; NOT REALLY ORDERED This pattern has a lot more order in it than you see, but human perception doesn't "see" the really strong ordering that is actually there. You can see through the confusion, by viewing the pattern stereoscopically.  Note the line of four dots at the bottom: cross or spread your eyes enough to fuse an adjascent pair. When you see the stereoscopic images, you can see the squares of nine that make wandering in this forest much easier.
Heat engines (auto engines, steam engines, etc) can do work only if heat can be transferred from a higher temperature to a lower temperature. If everything is at the same temperature, energy exchanges are completely random.  Billions of billions of molecules exchange energy at random, and that means that we can't expect more energy to be transferred from the hot gasses in the cylinder of an engine to the piston of the engine than vice versa.  The piston won't move.  The engine won't work. That many people are led to financial slaughter by the lure of the lottery is evidence that "random" can be an unseen concept lurking in the MAGIC zone.
Aristotle's "energy" is the thing in food and fuel that gives us and our machines "capacity for doing work." This is the big discovery of thermodynamics and the facts underlying entropy.

Entropy is a measure of probability that what we can say (about the behavior of molecules, etc) actually is.

Energy is a very abstract thing, but "we have no knowledge of what energy is."