“Where does “knocking on wood” actually come from?”

Dear Touching Wood,

I love this question, partly because the honest answer is: nobody knows for certain.

You will find many confident explanations. One says it comes from pre-Christian tree reverence. Another says it grew out of a children's game of tag. Another links it to Christian veneration of the cross. These stories are charming and widely repeated, but I have not seen firm historical evidence that settles any of them, and I would be wary of any website that tells you otherwise with great certainty.

What we can say is that sayings and customs of this kind belong to what folklorists study: traditions passed along informally, which change as they travel, and which often gather new origin stories along the way. As the Encyclopaedia Britannica describes it, folklore is transmitted by word of mouth and custom and is always in motion.

It helps to separate three things:

• History: what documents and evidence can show. Here, the evidence is thin.
• Interpretation: the meanings people give the custom. These are many, and they are personal.
• Efficacy: whether it changes what happens. There is no evidence that it does.

And yet the habit survives, because it does something else quite well. It acknowledges uncertainty, expresses hope, and links you to your grandmother. That is a perfectly good reason to keep it.

With warmth, The Wise Woman