Robinson Crusoe Explains Free Trade

“You remember how Robinson Crusoe managed to make a plank when he had no saw.”
“Yes; he felled a tree, and then, cutting the trunk right and left with his hatchet, he reduced it to the thickness of a board.”
“And that cost him much labour?”
“Fifteen whole days’ work.”
“And what did he live on during that time?”
“He had provisions.”
“What happened to the hatchet?”
“It was blunted by the work.”
“Yes; but you perhaps do not know this: that at the moment when Robinson was beginning the work he perceived a plank thrown by the tide upon the seashore.”
“Happy accident! He of course ran to appropriate it?”
“That was his first impulse; but he stopped short, and began to reason thus with himself:
“‘If I get this plank, it will cost me only the trouble of carrying it, and the time needed to descend and remount the cliff. But if I form a plank with my hatchet, first of all it will procure me fifteen days’ employment; then my hatchet will get blunt, which will furnish me with the additional employment of sharpening if; then I shall consume my stock of provisions, which will be a third source of employment in replacing them. Now, labour is wealth. It is clear that I should ruin myself by getting the plank. I must protect my personal labour; and, now that I think of it, I can even increase that labour by throwing back the plank into the sea.'”
“But this reasoning was absurd.”
“No doubt. It is nevertheless the reasoning of every nation which protects itself by prohibition…. Consider the nation as a collective being, and you will not find between its reasoning and that of Robinson an atom of difference.”

From Economic Sophisms, by Frederic Bastiat