Posted by: N.S. Palmer | November 14, 2013

Scientific Certainty? Oops.

By N.S. Palmer

How many chromosomes do human body cells have?

It seems like a simple question.

Until the 1950s, biology textbooks said that human cells have 48 chromosomes. That number of chromosomes was determined in 1923. American biologist Theophilus Painter counted them.

How many chromosomes do people actually have?

46. That’s the correct number, given by all current books.

From 1923 through 1956, everyone thought that people had 48 chromosomes because Painter mis-counted them. After that, nobody bothered to recount them.

That’s the power of conventional wisdom and groupthink. “Everyone knew” that human cells had 48 chromosomes, so what was the point of counting them? If you happened to count them and you didn’t get a total of 48, you simply assumed that you’d made a mistake. Everyone knew there were 48. Who were you to say otherwise?

Today, “everyone knows” that blood cholesterol causes cardiovascular disease. Ancel Keys got the ball rolling with some rather sloppy research in the 1950s. Most physicians have spent their careers telling people that it does. Their sense of self-worth is riding on the belief. Drug companies have made countless billions of dollars selling statin drugs as a result of that belief. They’ve got lots of money riding on the belief. Is it true?

It might be. But I remember the books that said human beings have 48 chromosomes. And I wonder.

Copyright 2013 by N.S. Palmer. May be reproduced as long as byline, copyright notice, and URL ( are included.


  1. […] See Palmer, N.S., “Scientific Certainty? Oops.” ↩ […]

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