Is knowledge also a belief?

I guess that you mean the laws of mseophysics, thus not those of microphysics and macrophysics. But even then, if you mean the mesophysical laws, it is not possible to be 100% sure. Knowledge about mesophysical laws has a likelihood of about 98-99% truth. The primary task of our senses and brains is not to know complicated laws but to support our surviving.

Yes, that is true, but one should also not completely mistrust a perception. :stuck_out_tongue: