We cannot know anything about physical reality, which is patterns of energy in the universe at points in time, with absolute certainty.
So you assume as true that physical reality is "patterns of energy in the universe." It's nice to see that you think you know that. You also assume that patterns exist. You also assume that energy exists. You also assume that there is a universe. You assume that time exists. You assume that points of time can be analyzed and distinguished.
For someone who is so absolutely positive that no definite knowledge exists... in order to make your point, you assume a lot of things to be incontrovertibly true.
But wait, I know what you will say... you know your assumptions by probability.
If you claim that you do not know these things for certain, but only by probability, then you must admit that there is a chance that you are wrong. This is inescapable. And if you are wrong, then we CAN know things about "physical reality."
NOW I SUMMARIZE:
You must decide whether you know your assumptions for sure, or not for sure. There is no third choice. These are your two options.
1. If you know your assumptions for sure, then you already wrong because you have definite knowledge about the physical world.
2. If you do not know your assumptions for sure, but only by probability, then you must admit that there is a chance that you are wrong.
You must choose one of these options. This dichotomy, as such, has only two options. Option 1 makes you contradict yourself. Option 2 makes you admit that your theory may be right, or may be wrong, and you will never know and neither shall we. So if that is your theory, why should I vote for it?
In other words,
Option 1 entails that we CAN know about the physical world with 100% certainty.
Option 2 entails that there is still a CHANCE that we really CAN know about the physical world with 100% certainty.