While science and Semir are at odds, these aren’t the first stone spheres to be found in the world. They are actually found all over the world. These spheres from Costa Rica seem to be man made and Semir even found some in the area, or at least visited them. So it is not out of the realm of possibility that he did, indeed, find something that was man made. The issue is that the spheres that are discovered like these are generally very smooth and created with tools, the ones he found seem to be much rougher and less deliberate in their formation. That isn’t to make a statement on which argument is correct, but it does give some credence to the argument that Semir is making about the stones he has found.