Intel (and presumably others) use formal methods to verify their hardware designs, or at least large portions of them. This started in earnest after the FDIV bug. Here's a presentation on the topic (dated now, but my understanding is the use of formal methods has only increased since then).
Software ... the part that software developers write ... is created to run on a strong foundation of CPU, GPU, NICs, RAM, PCI buses, SSD and so on (which the EE, ChemE, Chem, math, physics people make). That makes our stuff better than if it was software all the way down. HW is formally verified.
Ehm, what?