Magical darkness. Heavier than air creatures able to fly without corresponding wing surface area. Flying castles and carpets and mages. Temperature variations of hundreds of degrees in less than a second, then reverting back with no residual effect. Variable gravity. Cursed locations that are actually cursed (not just Hollywood Haunted Houses). Gods that exist and affect the material world in response to who-knows-what. High-, low- and wild-magic zones. Flaming swords that consume no fuel or oxygen. Creatures that can change your atomic makeup simply by looking at you. Storms that pay no attention to meteorology. Stars that follow their own path. Astrology that actually works.
Nature in D&D is not stable.
How do you formulate laws of physics in a world where the outcome of experiments is subject to random factors (the whim of the gods, wild magic) or factors you can't perceive (a curse applied to an ancestor of one of your lab techs, an auspicious day in a religion you don't follow)?
Physical laws that include "might completely change or become irrelevant based on the items you are attuned to" and "might not work based on how the nearest god feels about the situation" aren't all that great at being predictable or testable.
All the above means, is that the fundamental physics of our universe does not apply. Magic as described in the D&D manuals is actually evidence that science is possible in the average D&D 'verse. You do not do the incantations for fireball and get a cloud of butterflies or icecream in most D&D games. Astrology is a science if it works.
