Friday, May 7, 2010

Ancient Physics - Plato and Aristotle

Does ancient physics, dating from ~400 bc, have anything to tell modern science?

All we have from Socrates, Plato and Aristotle are writings, but they must have used diagrams of some sort. What would they have done given access to modern computer graphics?

The images [click on them for larger versions] are from a presentation I gave at the Philosophy Club here in The Villages, FL today. You can download the narrated PowerPoint slide show, click on: Part 1 and Part 2.

Here is a brief summary:

Plato's Analogy of the Divided Line

In The Republic, Book VI, Plato divides a line unequally. The first section is analogized to the Physical World and the second to the Intelligible World. Then, by the same proportions, he sub-divides each section. He analogizes the first segment, AB, to Shadows and Reflections of physical things; BC to the Physical Things themselves, CD to Mathematical Resoning, and DE to Philosophical Reasoning. Although Plato does not mention it, later commentators noticed that, by the given construction, it turns out that segment BC (Physical Things) is exactly the same length as CD (Mathematical Reasoning). What could that imply? I go into greater detail in the PowerPoint presentation.

Plato's Allegory of the Cave

Plato, in The Republic, Book VII, see first image above, imagines prisoners who spend their entire lives in a cave, looking at two-dimensional shadows on a wall. The prisoners give names to the shadows, learn to predict sequences, and speculate on their origin and meanings. They come up with the equivalent of religions, sciences and philosophies. Then, one prisoner is released into the real three-dimensional world and learns about physical reality. She returns to the cave but is unable to convince the prisoners of the reality she knows as truth. They make fun of her as a crazy philosopher.

Putting the Analogy of the Divided Line and the Allegory of the Cave together, the prisoners represent a low level of knowledge and understanding, represented as line segment AB. The prisoner released from the cave is at level BC, like ourselves. Those of us who have learned mathematical reasoning are not only out of the cave, but are at a higher level, CD. Finally, the philosophers among us, who understand the Idea of Forms and the Good and so on, are at level DE.

My question is, "Are WE really out of the cave yet?" Perhaps, if, as string theory postulates, there are actually 10 or 11 dimensions, those of us who perceive 3D + time are only about 10% better off than the prisoners in the cave, limited to 2D + time! In the PowerPoint presentation, I speculate on the possible equivalence of time and space.

Aristotle's Five Elements

Aristotle, like most of the ancients, believed there were only five elements: Aether, Fire, Air, Water, and Earth. Indeed, according to him, (see his Meteorology, Book I and his Physics, Book I) there is really only the Aether, the quintessence, the All. Fire, Air, Earth, and Water exist potentially in each other, and all can be resolved into the Aether. This is not far from Spinoza's belief that there is only the Universal Substance, and all things that seem as different as material and spirit are merely different aspects of that Universal.

How ridiculous is this? Well, not so ridiculous as the PowerPoint Show explains.

The names of Fire, Air, Water, and Earth in the image are ambigrams, which read the same right-side-up and upside-down. They are featured in the famous book and movie, Angels and Demons.

Read more detail about Aristotle's Five Elements at my Google Knol.

Ira Glickstein


Howard Pattee said...

After summarizing Plato’s allegory of the cave, Ira wonders, "Are WE really out of the cave yet?"

Science has a clear answer: Not only are we still in the cave looking at shadows, but we have no possibility of looking anywhere else! Science has taught us that we can only construct experiments to verify our shadow images. Since we can’t leave the cave, we never get reliable answers by speculating about “what’s really out there” casting the shadows.

Francis Bacon is credited with early promotion of this experimental attitude: "Men have sought to make a world from their own conception and to draw from their own minds all the material which they employed; but if, instead of doing so, they had consulted experience and observation, they would have the facts and not opinions to reason about, and might have ultimately arrived at the knowledge of the laws which govern the material world."

In 1662 (a year after Newton entered Trinity College as a “work-study” student), Charles II chartered the Royal Society to promote experiments unhindered by philosophical speculation and religious doctrine. Listen to a humorous talk by Nobel Laureate Kary Mullis on the beginnings of the experimental method. (Global warming doubters will enjoy his talk.)

This epistemology limitation of modern physics was stated clearly by Heinrich Hertz: "We form for ourselves images or symbols [Plato’s shadows] of external objects; and the form which we give them is such that the logically necessary consequents of the images in thought are always the images of the necessary natural consequents of the thing pictured. For our purpose it is not necessary that they [the images] should be in conformity with the things in any other respect whatever. As a matter of fact, we do not know, nor have we any means of knowing, whether our conception [the shadows] of things are in conformity with them in any other than this one fundamental respect."

Ira Glickstein said...

WOW! Thanks Howard for the Kary Mullis TED Talk link!

He gave the talk in 2002 way before Climategate and he is spot-on on the subject of Global Warming. Interesting the talk was posted to the Internet only last year. (I wonder why the delay.) I plan to post that link to WattsUpWithThat so my skeptic-lukewarmer friends can enjoy it.

Mullis is also excellent when describing the reason King Charles II founded the Royal Society of London in 1662 and their role in establishing the experimental method as the standard for modern science.

Mullis's youthful rocket experiments brought me back to some of my chemistry and electrical experiments in the one-bedroom apartment where my parents, my younger brother, and I lived. Yes, I melted powdered sulphur over an alcohol burner (purchased at the Gilbert Hall of Science in Manhattan where you could get all sorts of chemicals and magnets and great stuff) and dipped wooden matches into it. When struck, the sulphur coating on the matches would really light up and stink. More than once, the liquified sulphur would catch fire and I would have an entire spoonful of it go off in my face. My dad also got me a spark coil from a Model T (10,000 volts) and I made a "Jacobs ladder" and got more than one shock. Whenever my experiments resulted in lots of smoke I would close the windows so the neighbors would not call the fire dept!

Mullis received a Nobel Prize for the Polymerase Chain Reaction (PCR) method of amplifying DNA. Around ten years ago, my son-in-law showed me PCR in his post-grad lab at Harvard. Fantastic idea.

Yes, Howard and Mullis are correct about the need to discard dogma and do real honest experiments. This includes not only religious dogma, but also preconceptions held by "authorities" from the last generation. He is also spot-on about some of the science sponsored by governments that often is run by the "authorities" of yesteryear plus politically-connected opportunists and corporations that are in it for the money.

Yep - we are still in the cave, but standing on the shoulders of giants (great scientists of the past) and therefore (perhaps) at a slightly higher level.

Ira Glickstein