Your experience is nothing but a series of electrical signals interpreted by your brain.
All senses translate to electrical signals. External stimuli generates a chain reaction that must be interpreted by the brain before it can be understood.
Your own consciousness is never objective. It is filtered through neural shortcuts that your brain has been developing since you were a child. What seems obvious to you can be completely alien to someone else, with a different life experience.
In fact, with an advanced enough technology, all our senses could be mimicked by simply pulling our brains out of our heads, keeping it alive somehow, and feeding it the exact same signals that our bodies would normally produce.
Our brains would be unable to distinguish between the artificial and the natural signals. Therefore, we would never know if we were living in a simulation.
Thus, because the burden of proof is always on the person trying to rebut the outlandish claim, we are living in a simulation. You can tell cuz some folks think the earth is flat. See? Airtight.
YOUR MOVE, INTERNET.