memes

I do. I claim that trade can destroy value, and it can destroy value that is created through labour just as much as it can amplify it. A change in how much people value something can turn productive labour which produces valuable goods into a worthless activity which wastes time.

If tomorrow, people suddenly decide rice is disgusting, repulsive, and not fit for human consumption, that would destroy all the value in rice production equipment, and it would destroy the value of all the rice that has been produced but not consumed. The rice hasn't changed. The nutritional value hasn't changed. But since rice no longer makes people happy, its value is now far less, regardless of how much labour was expanded to produce it.

There is no objective standard for value. Value is inherently subjective. Not even for food. After all, dandelions are edible, but also perfectly worthless because it's simply culturally unacceptable to eat them. Blackberries are another great example. In your area they might be a rare and expensive delicacy. In my region, they grow like weeds and we pay people to remove blackberry vines.

For a similar reason, we could pour as much labour as we want into producing mud cakes, but no matter how much work it was to make them, mud cakes are worthless to everyone and so there is no surplus created by making them. Instead, everyone who expended resources (money, equipment, labour) to make them has incurred an economic loss because the resources were consumed and nothing valuable was received in return.