they consider critical to humanity's future. Joy warns that the technology could be used by elites for good or evil. They could use it as "good shepherds" for the rest of humanity or decide everyone else is superfluous and push for mass extinction of those made unnecessary by technology. Advocates of the benefits of technological change typically see emerging and converging technologies as offering hope for the betterment of the human condition. Cyberphilosophers Alexander Bard and Jan Söderqvist argue in The Futurica Trilogy that while Man himself is basically constant throughout human history (genes change very slowly), all relevant change is rather a direct or indirect result of technological innovation (memes change very fast) since new ideas always emanate from technology use and not the other way around. Man should consequently be regarded as history's main constant and technology as its main variable. However, critics of the risks of technological change, and even some advocates such as transhumanist philosopher Nick Bostrom, warn that some of these technologies could pose dangers, perhaps even contribute to the extinction of humanity itself; i.e., some of them could involve existential risks. Much ethical debate centers on issues of distributive justice in allocating access to beneficial forms of technology. Some thinkers, including environmental ethicist Bill McKibben, oppose the continuing development of advanced technology partly out of fear that its benefits will be distributed unequally in ways that could worsen the plight of the poor. By contrast, inventor Ray Kurzweil is among techno-utopians who believe that emerging and converging technologies could and will eliminate poverty and abolish suffering. Some analysts such as Martin Ford, author of The Lights in the Tunnel: Automation, Accelerating Technology and the Economy of the Future, argue that as information technology advances, robots and other forms of automation will ultimately result in significant unemployment as machines and software begin to match and exceed the capability of workers to perform most routine jobs. As robotics and artificial intelligence develop further, even many skilled jobs may be threatened. Technologies such as machine learning may ultimately allow computers to do many knowledge-based jobs that require significant education. This may result in substantial unemployment at all skill levels, stagnant or falling wages for most workers, and increased concentration of income and wealth as the owners of capital capture an ever-larger fraction of the economy. This in turn could lead to depressed consumer spending and economic growth