That is not a sure proof. This could all be happening in your imagination for all you know. A dream within a dream within a dream. So you are just assuming your physical senses are telling you something. You, and I, are forever ignorant. You are not the creator and so you'll never know anything with absolute certainty. You don't even know if there is a creator.
For now all we can do is make the assumption that science is our best tool for judging "reality". Well I'll go with that over religion and most of the other bullshit humans are prone to but I do not anymore assume it's true. It may be, it seems to be at times (see your statement about gravity), but so what? I have a very limited perspective and very little information. In fact I don't have any I can ultimately count on as I said above.