The above picture is what was the modern day "scrapper" of the 1870's. It was brought to the farm undoubtedly by schooner ship and was very likely the first piece of heavy equipment in an 80 mile radius. A team of oxen were used to pull the pre-industrial piece of machinery and the levers in back of the shovel were driven into the earth by men. It was primarily used to scoop earth making a ditch and dumped making a road bed. This process of making roadway is still used today.
Progress: a proceeding forward; advancement or improvement in mental, moral, or physical condition. growth or development. source The Winston Dictionary, Advanced Edition, 1946.
Back to Duncan's Olduvai theory, the first phase of human history basically was when simple tools and weak machines (like the one pictured above) limited economic growth. The second "industrial" phase encompasses modern industrial civilization where machines temporarily lift all limits to growth. The final "de-industrial" phase follows where industrial economies decline to a point of equilibrium with nonrenewable resources and the natural environment.
Without getting too technical and looking at a worldwide view, it might be fair to point out that we're probably in the latter stages of the second "industrial" phase. Not quite yet in the third phase. The instructors thought that once global progress ceased, the die-off would soon begin. Furthermore, once forward progressed stopped, there would be a "pause" before another direction or decline could take place. An example of this might be that a train must come to a complete stop from going forward before it can go in reverse. Pauses can be very hard to spot, when looking at market trends for example, sometimes they are only realized in retrospect. However, what we're talking about here is a break within the 100 year industrial life span. Perhaps, the severe recession we had during the early 1980's, was this the pause in this country? This is mighty close to what Duncan predicted to happen in 1979. Have we progressed beyond this? The answer is, yes, beyond a doubt, we were still growing beyond 1979! Correct? We cannot continue growing in population, economy, and extraction of resources, once the extraction of those resources begins to diminish! Of course, all resources are not all going to diminish at once, making it extremely hard to pin point when the scales actually dip the other way. An example of a diminished resource could be the fisheries of the world.
Even though, I believe we have declined here in North America for the past thirty years, we are becoming more and more a part of a global economy that hasn't. Hasn't this actually "masked" our true situation in this country? Thinking of Russia, without a doubt, they have come back and their standard of living continues to grow from the early 1990's when the former Soviet Union collapsed. Look at the growth of the economies of India and China! Another notion the instructors had, is that there would very likely be a explosion of resources extracted and consumed toward the end of the "age of progress". I am certain, they were thinking of terms of 1930- 1970, however they are still correct in that respect, only that there's a lot more resource than they dare imagined. Of course, this only makes sense as it would require more resource to maintain the population.
The instructors all believed that once the world ceased to progress, there would be a short pause and then we would start our descent. That this era will be short lived and marked by power outages, finally bringing down entire electrical grids around the world. That is, once electrical generation was decoupled with mass production of parts (one cannot happen without the other and this actually defines the industrail society), this present environment (age of progress) would end adruptly. At that point, the industrial society (age of progress) could not support the population it created. Once that happened, the die-off would begin in earnest, end of story (the instructors would not speculate what might happen after that).