The review confuses psychological optimism with a problem-based definition of optimism: that problems are solvable (and hence progress is possible). As David D

The review confuses psychological optimism with a problem-based definition of optimism: that problems are solvable (and hence progress is possible). As David Deutsch points out in The Beginning of Infinity, Winston Churchill was an optimistic leader and a fan of science and progress who nonetheless suffered from depression (the 'black dog') [1]. Whereas Thomas Malthus (mistakenly) predicted mass starvation due to population growth [2] and was therefore a pessimist who nonetheless was of a sunny disposition and the life and soul of dinner parties in London. [1] https://www.goodreads.com/book/show/10483171-the-beginning-of-infinity https://www.goodreads.com/book/show/10483171-the-beginning-o... [2] An Essay on the Principle of Population (1798) http://www.esp.org/books/malthus/population/malthus.pdf http://www.esp.org/books/malthus/population/malthus.pdf