We don't know, nor strictly speaking can we even say it's probable that the laws of nature will continue to operate. But we have to assume nature is uniform, otherwise we couldn't act in the world at all (if, indeed, the world didn't just disappear).
So, if I release a ball, why does it fall downwards? Why not just stay there? Or accelerate upwards? Or suddenly disappear? Or turn into a beautiful woman?
When I first studied philosophy, I couldn't grasp this. I thought, why doesn't past experience render it at least likely that the laws of nature will continue? It was a revelation when I finally got it. One of the few occasions in my life when I suddenly grasp something, and I thought, "oh wow" and "this means that everything we know is ultimately a type of faith". It added to the mysteriousness of this reality we find ourselves in, and the fact we ultimately know nothing in a strict sense.
