One prediction seems solid: The coronavirus epidemic will get much worse in the United States in coming weeks. But where the stock market is heading is much less certain.

It is too simple to assume that with its steep decline, the market has already discounted epidemiologists’ forecasts for Covid-19. By this logic, the stock market would fall further only if the virus turns out to be worse than forecast.

But the world has never seen an event quite like this before — a new pandemic that is being aggressively throttled by draconian shutdowns of whole industries, and by confining millions of people to their homes. The tools of statistical analysis and machine learning, powerful as they are, can’t adequately assess what the world is experiencing. There isn’t any stock market experience that is entirely analogous.

I believe the pandemic’s effect on stock prices today is better understood as a series of emotional responses to unique events. People are trading stocks with their cellphones on their living room couches with the television news blaring about the pandemic. There is widespread foreboding, not just about the economy but about the possibility of grave illness or death in the weeks ahead.