Describe the graph depicting continual human progress over time.

In Chapter 6: Under the Hide, O'Connell discusses a particular graph depicting continual human progress over time. The idea that humans would automatically continue to evolve and progress in a positive and efficient direction was taken for granted in past centuries, O'Connell states. Now, however, most scholars studying the issue in a quantitative way feel that the graph's upward trend is not a foregone conclusion, due to the way in which humans have abused the earth in recent years. O'Connell states most experts believe that the graph we have taken for granted "has been fatally undermined in our time" (143).