Why are any patents granted? I've yet to read a patent that wasn't just Maxwell's equations, quantum mechanics, and general relativity which are all just laws of nature and not patentable.
As far as software goes, here's a question that can be interesting to ponder. Suppose there was some clever, useful, non-obvious entirely mechanical invention that was patented. If someone else tried to sell a product that accomplishes the same thing as that invention by having a computer running a general purpose physics simulation program which is given a model of that patented invention, would that be an infringement of the patent on the mechanical device?
> would that be an infringement of the patent on the mechanical device?
No because a patent has to describe the mechanism (the non-obvious inventive step). If there are multiple ways to achieve the same thing then in practice it's hard to protect and the patent is probably worthless, if not too obvious to be granted in the first place.
As far as software goes, here's a question that can be interesting to ponder. Suppose there was some clever, useful, non-obvious entirely mechanical invention that was patented. If someone else tried to sell a product that accomplishes the same thing as that invention by having a computer running a general purpose physics simulation program which is given a model of that patented invention, would that be an infringement of the patent on the mechanical device?