Although the technologies described above appear to have the most promise for significant global effects, such foresights are plagued with uncertainty. As time progresses, unforeseen technological developments or effects may well eclipse these trends. Other trends that because of technical challenges do not yet seem likely to have significant global effects by 2050 could become significant earlier if breakthroughs are made. Consideration of such “wild cards” helps to round out a vision of the future in which ranges of possible end states may occur. Novel Nanoscale Computers In the years following 2050, serious difficulties in traditional semiconductor manufacturing techniques will be reached. One potential long-term solution for overcoming obstacles to increased computational power is to shift the basis of computation to devices that take advantage of various quantum effects. Another approach known as molecular electronics would use chemically assembled logic switches organized in large numbers to form a computer. These concepts are attractive because of the huge number of parallel, low-power devices that could be developed, but they are not anticipated to have significant effects by 2050. Research will progress in these and other alternative computational paradigms in the next 15 years. Molecular Manufacturing A number of visionaries have advanced the concept of molecular manufacturing in which objects are assembled atom-by-atom (or molecule-by-molecule) from the bottom up (rather than from the top down using conventional fabrication techniques). Although molecular manufacturing holds the promise of significant global changes (e.g., major shifts in manufacturing technology with accompanying needs for worker retraining and opportunities for a new manufacturing paradigm in some product areas), only the most fundamental results for molecular manufacturing currently exist in isolation at the research stage. It is certainly reasonable to expect that a smallscale integrated capability could be developed over the next 15 years, but large-scale effects by 2050 are uncertain. Self-Assembly Though unlikely to happen on a wide scale by 2050, self-assembly methods (including the use of biological approaches) could ultimately provide a challenge to top-down semiconductor lithography and molecular manufacturing. xvi Infova’s Global Technology Revolution.