Charlotte Moser on Forecasting

My comment:

2:30 If we knew the initial conditions perfectly, .... But but but, .... you have a model, right. Your model has some representation of state, and some set of functions mapping state changes as a function of time. So the "initial conditions" you are referring to are the initial states as represented in your model. Surely yes, because even if your model was using states of individual atoms then it would only represent them with some finite amount of data, so to a limited resolution. So your model is always representing not actual physical states, but statistical distributions of physical states. So there is no real way I can understand what knowing initial conditions perfectly could mean. Even if the model was subatomic, there is no notion of perfect knowledge of the state, because, even if it exists, it's hidden until you measure it. The reason I am making a fuss about this is that it is getting the notion of determinism wrong. There is an idea around that determinism is because fundamental material follows only physical laws, so the only things that can happen are what are predicted by those laws, but that's not how it is. Determinism only exists at the level of preparation of states which is something we do in a laboratory, or which states we simply assume hold in a certain situation in the real world, but these are never things we know in any sense where we could speak of perfect knowledge. The laws as we know them are really laws about our ability to prepare states of physical matter and energy and to observe how they change by selecting certain aspects of the material using instruments to measure pressure, temperature etc.

See The Category Enriched over the Category of Finite Sets, The Finitely Triangulated Manifold and the Magnitude of a Finite Category.

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