Theories that explain everything

Two ways of explaining things are by Intension (with an ‘s’) and Extension. 

The Intension is the list of properties that the thing you are explaining has. Thus for ‘journalist’ you might list dealing in news, writing in newspapers or magazines, communicating on current affairs by radio, television or social media.

The Extension is made up of the members of the class. Thus for ‘journalist’ you might list Owen Jones, Polly Toynbee, Charles Moore, Adam Boulton or Nick Robinson. These names convey to the listener or reader the idea of ‘journalist.’

The more properties listed in the Intension, the fewer the number in the class being talked about. ‘Animals’ has a great many members, but ‘human animals’ are in much smaller numbers, and ‘living human animals’ are in even smaller numbers. ‘Living human male animals’ cuts the numbers further, and ‘living human male animals living in Milton Keynes’ cuts them even more.

The more properties that are listed in the Intension, the fewer the number there will be in the Extension, and vice versa. The Intension is inversely proportional to the Extension.

I = 1/E

If there is an infinite number in the class, then E = ∞ and I = 1/∞ which is zero.

This means that if everything is in the class, the Intension is zero. A theory into which everything fits thus has no information content. Another way of putting this is to say that a theory that explains everything tells us nothing. Perhaps it tells us about its holder’s determination to apply a preconceived interpretation to everything in the observed world, but it tells us nothing about that world.

If a Marxist tells us that everything that happens can be explained by the theory, then Marxism can tell us nothing about what happens. Theories have to live dangerously, as Popper put it. There have to be circumstances that would lead us to discard or at least modify the theory if they were to happen.

Einstein, whose theory predicted that two stars observed during an eclipse would be out of their expected positions because their light would have been bent by gravity, could have seen his theory contradicted if this had not happened; but it did happen.

There appear to be no circumstances in which the theories of Freud or Marx could be contradicted if everything that occurs can be explained in terms of the theories. Their adherents use them to explain everything in terms of the theory, and theories that explain everything tell us nothing.

If everything that happens is confirmation of the theory, it has zero content.