I continue to dwell on Max Planck's assertion:

“A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.”

Life expectancy for a 50-year-old living in the UK has increased by ten years during the past century. Some of our sharpest thinkers aim to increase it indefinitely.

An ironic consequence of their possible success: the longer we live individually, the shorter the human race will survive collectively. When generations are replaced at a slower rate, species are slower to genetically adapt to environmental changes.

A second irony: longer life spans slow the acceptance of scientific truths that could further lengthen life spans.

Kurzweil suggests that life spans will advance at an exponential rate, but the truth is the opposite. Immortality is asymptotic; the closer we get, the slower we'll go.