I would argue that in any intellectual enterprise, that there are always assumptions that must be made. Once we make these assumptions, we proceed as if we never made the assumption and we take that assumption to be de facto true. Does the computer you used to type your post exist? It may or may not, but you go about using it as if it is. Does Hashem exist? With 100% probability, I can’t say for sure, but I go about my life k’ilu he does exist because I made the conscious choice to bridge the probability gap (as I like to say) and assume that he does.
As you point out, science is no different. Also as you point out, we must assume that there is indeed science out there to discover in order to make it a worthwhile endeavor. We must also assume that these laws we seek to discover are the same today as they are tomorrow, or else what is the point of discovering them today (assuming it was even a 1 day job, which it most certainly isn’t)?
Without dragging on, my main point I wish to bring out is that those who criticize science for these underlying assumptions and use these assumptions to lower science’s credibility as compared to other disciplines are mistaken, as these types of assumptions must always be made (though many times they are quite implicit and the unassuming may glance over them).