Archive for October, 2009

Meandering across the digital divide II

October 29, 2009

In his book The Step to Man, John Rader Platt predicted in 1966 that the time would come when there would be enough computer memory available that every thing that had ever been written could be stored digitally for our retrieval. As I recall he also posed the question that the technology evokes: what to keep and what not to.

We are close to being there and certainly are dealing with the question. I ran into it while trying to locate a favorite article of mine: Bela Julesz: Cooperative Phenomena if Binocular Depth Perception (American Scientist Vol 62 No 1 Jan-Feb 1974). I knew I had it on my bookshelf, but I couldn’t remember the date or the author’s name. All I had was the notion that I could remember the cover picture, if I saw it. Turns out I did. It’s a sea turtle. But rather than committing myself to searching through all my back issues, I thought I would let google take a stab at it. So I put in “random dot stereograms” and came back with Julesz name. I went to the American Scientist website and put in Bela Julesz, and got NOTHING!! Now that is a crime, and a lesson of some sort. So I started leafing through the back issues on my shelf, searching now for Julesz on the content page. Got it!

The thing about this article is that it reproduced an almost full page random dot stereogram, paired red and green dots arranged by computer in stereopairs on an arbitrary geometric surface, accompanied by red and green lensed filter. You hold these filters over your eyes and wait while the brain begins processing the data. Minutes go by, while this goes on. Slowly, the form begins to emerge. Finally, you see the whole form. You can almost hear the two sides of your brain chattering away about which red dot goes with which green dot to produce a coherent form. It is a very convincing experience that says you see the world as a constructed image.
I have re-checked the image and my eyes can still construct the form relatively quickly, though not immediately after several years-since the last time I did this.

But the article was not reachable by searching the Sigma Xi/American Scientist site. At AAAS you can access John Platt’s  piece on Strong Inference, and T C Chamberlain’s Multiple Working Hypothesis classic. You can read Leonardo’s handwritten notebook. So it’s easy to think that you have available a world of literature. And it’s easy to get to.


Unless someone who has a budget to cover it, and the sense to recognize its meaning, material produced prior to the digital revolution can be left un-scanned on the shelves, somewhere in the stacks. But who has un-prioritized time to meander through the stacks  just looking at  not looking for? Well, retired old men, but who else.

Compounding the situation in geology  is the coincidence of the digital divide with the conceptual divide generated by the avulsion-I just learned this word, as it applies to meandering rivers making major changes in  course- from Geosynclines to Plate Tectonics.  It is easy for the younger generation to feel that there is nothing meaningful to look for back in the stacks.

That makes it easy, in turn,  for a person from the older generation to complain about the contradiction of students of a historical science ignoring the history of their own science. Fortunately, science types learn that doing hard but meaningful things can be a lot of fun!

Here is another photo of Alamere Falls. The stream here is running straight down the steepest slope, fulfilling the common expectation.

Alamere Falls 2005

Alamere Falls, February 2005 from


Meandering across the digital divide I

October 27, 2009

Earlier this month, I made a comment on Highly Allocthonous and followed up by posting here the scanned photos below. Subsequently, I removed the photos and am now returning to the project.

Textbook illustration,

As is usual for me, I am writing from a title, not knowing exactly where it’s going, but with some confidence that it is going somewhere. Meandering, in a way. But then the sinuous movement of flowing fluids themselves are the consequence of not of complete disorder nor of a form imposed on it externally, but rather seem to be an expression of some aspect of turbulent flow. Turbulent flow, of course, is in the domain of physics, somewhat to their chagrin. I have been happy to leave the subject there in my teaching of introductory geology.

The digital divide is not so simple either. I have encountered it within the faculty of my college, certainly within the classroom, in my doctor’s office, anytime one does some kind of literature search. I wondered when I made the comment if the image that I was familiar with was, in fact, across the divide from the author of the post, who gives every impression of being diligent, competent and energetic in her pursuit of science. From the response, I tentatively conclude that was indeed the case.

The digital divide is multidimensional, and I will do some more meandering around it. Perhaps there is a basin along it somewhere. I didn’t know that there is a basin in the Continental Divide until I was driving through Wyoming on day. Singing a Sara Carter song, actually.

“Go a-railroading on the Great Divide

Nothin’ around me but Rockies and sky..”

For now I will leave you with a favorite photo of a meandering stream from a 1979 Sierra Club calendar (by Steve Manning).

Alamere Falls, prior to 1979

Alamere Falls, Pt. Reyes, California.