Formulate the loss function -- you'll find it's just

    loss(the-right-answer(perfect-x) - perfect-y)

The most important aspect of "the-right-answer" is its ability to ignore almost all the data.

The existence of planets is "predictable" from the difference between the data and the theory -- if the theory is just a model of the data, it has no capacity to do this.

If you want to "do physics" by brute force optimization you'd need to have all possible measures, all possible data, and then a way of selecting relevant causal structures in that data -- and then able to try every possible model.

    loss(Model(all-data|relevant-causal-structures) - Filter(...|...))) forall Model 

Of course, (1) this is trivially not computable (eqv. to computing the reals) -- (2) "all possible data with all possible measures" doesn't exist and (3) selecting relevant causal structure requires having a primitive theory not derived from this very process

animals solve this in reverse order: (3) is provided by the body's causal structure; (2) is obtained by using the body to experiment; and (1) we imagine simulated ways-the-world-might-be to reduce the search space down to a finite size.

ie., we DO NOT make theories out of data. We first make theories then use the data to select between them.

This is necessary, since a model of the data (ie., modern AI, ie., automated statistics, etc.) doesnt decide between an infinite number of theories of how the data came to be.