What kept him in the market and keeps people in today as well is faith that the market will eventually recover and continue to mark new highs.  That's been the history over the last 100 years.  The only variable is the length of time it takes to reach new highs.  So if you invest wisely (money you don''t need for a long long time) you don't need to fear the impact of a depression or recession.  Personally, I was in the market back then and stayed in.  The value of my investments plunged by a third at the low point, but they are worth far more today than they were back then and will be worth even more in another 10 years.  Of that I am reasonably sure.