It is true, you cannot do science without speculation. And it doesn't matter if you speculate before or after gathering a particular set of data, speculation is

It is true, you cannot do science without speculation. And it doesn't matter if you speculate before or after gathering a particular set of data, speculation is still required. I didn't say that you shouldn't test your model, was just pointing out that you can model something based on an incomplete understanding and it can still be considered part of the scientific process before you have gone and checked your results. It can even be science even when there is currently no known way of checking the results, as long as you can point to a reasonable path that might lead you there. Chaotic models are used in prediction. Regularly. Computational fluid dynamics wouldn't exist as a discipline without this. And I never claimed that you should draw your final conclusions from a model, just that they can be a fantastically useful tool for exploring the unknown. They can also be a trap if you trust the model more than the data, but that isn't the fault of modelling.