Nassim Nicholas Taleb has written a piece on futurism which is making me feel, well, contradictory. Apologies for my writing: fighting a killer headache this week.

Taleb asserts that the present has changed little from the past; that “futurists always get it wrong”, and that if we wish to envision the future we should subtract from the present things which do not belong. I believe the present is so different from the past that it would be shocking to humans from even a few centuries ago. Technology is culture, and our immersion in culture makes it quite difficult to understand just how unusual we are.

My great-grandparents were immigrant farmers. Most people were: prior to industrialization in the late 1700s, the vast majority of humans grew their own food or were engaged in providing it to others. Now worldwide, only a third of our workers grow food. The US’s agricultural output has almost tripled over the past sixty years, a result of phenomenal improvements in efficiency made possible by the widespread use of petrochemicals–an energy-dense store only accessible for the past few hundred years. That same industrial revolution cut the fraction of our population employed in agriculture from 75% to only 3%.

We’ve been talking at the office about wireless devices receiving video. I’ve been wondering: will cell phone data services keep getting faster? Or is 4G actually running up against the physical limits of the spectrum?

As it turns out, the Shannon entropy limit for these kinds of channels is roughly 6 bits/second per Hz. 4g radios are approaching 5 bps/Hz. Technologically, at least, we’re almost out of room. We can push about 50Mbps over a 4g link, given the allotted frequency space for wireless data. The only real improvement we can make is to repartition the spectrum.

Wolfram Alpha to the rescue!

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