Physicist: It helps to first get an idea of how the double slit experiment is done. The double slit experiment works for any particle, but in what follows I’ll use light to avoid confusion. Even so, this cat-astrophe is not the biggest problem with the cat-based double slit device. In order to do the double slit experiment, especially when tiny wavelengths are involved, it’s very important that all of the particles involved are exactly identical and in phase. And once the 330 quadrillion light year long double slit apparatus is set up, you’re ready to go!