Even if you turned out to be right about a continuing tumble in 2019, the great risk would be that whenever the rebound began, you would be caught out of position, unable to take advantage.

Suppose you were clever enough to recognize at the start of December 2007 that a major recession was about to take place, and you moved your money out of stocks.

Yes, you would have saved yourself from steep losses in 2008 and early 2009. But you have to ask yourself: Would I have also had the courage to put money back in while the economy was still in horrendous shape in 2009, with double-digit unemployment and a banking system in tatters?

If not then, when would you have moved money back in? People who simply left their savings fully invested in the stock market in December 2007 have now made a 134 percent return on that money. Would you have done better than that, or would you have missed out on a big chunk of those gains out of the same caution that led you to pull money out of stocks to begin with?

People who did not panic in the fall of 2008 — the most panic-worthy time in most of our lifetimes — and kept putting their retirement funds into stocks did indeed incur steep losses over the ensuing months. But their newly invested funds were being put into stocks at the most favorable valuations in a generation, and thus enjoyed the full benefit of the rebound when it eventually came.

A truism of economic and financial cycles is that by the time it feels like the coast is clear and putting money into riskier investments is completely safe, the real money has already been made. People who looked at the economic chaos of early 2009 and stuck to their guns have ended up far better off than those who, convinced that a double-dip downturn was imminent, waited for years to get in.

This equation changes, of course, if we’re talking about money needed imminently as opposed to longer-term savings, such as for retirement. The economy looks stable now, but that could change — it’s still possible that markets and C.E.O.s know something about the future that isn’t clear in the data yet.