Forget math, engineering, medicine, chemistry, agriculture, and all the conveniences of modern life: Why don't we go right down to stuff even animals can figure out?
If you've ever done anything in your life as rudimentary as seeing if something that worked once works the second time you try it you've dipped your little toe in the most fundamental basics of the scientific process. If you ever tell someone what you did and that it worked they can try it themselves. If it works for them they confirm it was true. If it doesn't you find a flaw in your assumptions or realize there was a detail you overlooked. That's the basics of peer review. Working off confirmed information it gets passed along to yet another person, who may eventually find you get different results in different conditions, then make a note of each condition and the result, refining understanding. Repeat as necessary, adding new observations and eliminating false information.
It's like learning to hunt and gather. When foraging you make a note of the things you eat. Stuff that makes you sick goes in one column, stuff that's edible goes in another. Very straightforward. You notice if some things look alike but some make you sick and some don't you note other things like how it tastes or if there's something different about where it grows, or if it's got funny lumps and spots. If you're smart you also take note of what eats it besides you. That's basic data gathering. Share it and confirm it and until there's new information it becomes fact. Hunting game is a little more advanced because some things are harder to confirm. Every time you approach an animal you figure out what causes it to run away. You do that by observation, and you repeat it to see if it works figuring out early on that if an animal sees you it will run and soon after that if it hears something it will startle. These results are consistent, but even mitigating them does not ensure you will reach the animal. Later when working with this information you or someone using your methods may start wondering if there's something you can't see or hear that alerts the animal. They make a note of the days they go hunting and catch something. They find they have better luck in certain weather. First they assume that it was the weather itself affecting the animals but later when somebody gets the idea that animals can smell someone approaching and wind or rain affects detection that narrows down the real cause, eliminating a false assumption. Even killing an animal effectively is more involved than chucking a rock and hoping for the best. You note where the animal was struck that hurts it the most, cut up the meat and see the damaged organs underneath gaining an understanding of the wound that killed it. Improve technique, improve tools, share and pass it along.
Observe, test, record, confirm, update, repeat. The scientific method in a nutshell. Just as applicable to someone wearing a loincloth as a labcoat.
Or you could run around never asking questions. Never sharing information. Never making connections. Never thinking about the whys and whats and ifs. Never thinking, period. Never remembering anything and expecting the same result from different actions and different results from the same actions because attempting to make any kind of rational sense of the world even at the most basic level of personal observation setting up something as simple as a true/false diagram sounds too much like science to say nothing of relying on information already collected because your entire premise is to call into question the validity of every scrap of recorded data and the method behind their collection in the whole of human history except one book of varying personal accounts revised through the ages that is neither internally consistent or an accurate depiction of observable phenomena as measuring tape and a hula hoop will show.
