I think people are confused about
- What a model is.
- What a model does.
We should talk about what it means to get the "right answer" in the context of modelling as well.
Bakustra wrote:
Okay, let's take a look at two examples that shatter the hopes of a general model.
Henry VIII broke from the Roman Catholic Church
Hitler
Let us first of all think about reality. Actual reality is the greatest simulation of events. It has all the mechanisms and works everything out exactly. Lets take the reality simulation backwards in time and let it go again. I can guarantee you that if we ran our reality simulation again from far enough back then Hitler wouldn't exist in the second realisation of 'reality', nor the third. I would say that the variations within our possible histories are larger than the variations between the histories of possible worlds. That is the real power of chaos.
To say that
any possible model is wrong if it does not predict Hitler (or any other specific event) is a useless metric. If reality itself wont give us what we got the first time, how on earth is any model we can make going to work?
What is a model actually meant to do then? I'll take an example of something highly random that is modelled to illustrate this: an epidemic. A model is meant to be something that is a representation or reality that captures the essential features of a process. It should not be a total simulation. You would never get anywhere trying to model an epidemic by tracking individual spores or viruses, it needs to work at a higher level if it is going to be of any use. The model cannot and should not try and predict the specifics of a highly random process. It is useless to ask a question about an epidemic such as "will this specific person, Joe, get sick?", instead you want to get at more abstract quantities, such as what is the expected total number of people that will be infected over the course of the epidemic, or what is the probability that a certain region is infected.
You see modelling of highly random processes every day. The weather is, despite being completely described by physics and fluid dynamics, predicted with statistical methods. There is no way of knowing if it will rain tomorrow for certain, but they can give you a
probability of rain. This is not perfect, but it is very useful.
A a useful model is one that distils reality down and gives actual
insight into the processes that are occurring.
For example, a model that describes the interaction of nations based on their natural resources would be a useful thing to have. If you can assess how nations behave when they have XYZ around them then you have gained some insight into history. It doesn't matter that a monarch could act totally contrary to the model in a certain situation to seduce his sister.
Any model of history should not be expected to just simulate everything, nor should it be dismissed just because it does not say that person X should die at time Y. To dismiss all attempts at models for history because they will inevitably be 'imperfect' when held against the standard of the one specific history we happened to get is a terrible idea.
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