An algorithm that computes 22+117 or something like that is free to compute it correctly, even as it’s running on a physical computer that might be broken in a subtle way, possibly producing a different result. Identifying with an algorithm that your brain currently implements when making a decision doesn’t seem different, you are just a more complicated algorithm, producing some result. What the physical world does with that result is a separate issue, but for purposes of this argument the algorithm is selected to be in tune with the world, it’s an algorithm that the brain is currently simulating in detail.
An algorithm that computes 22+117 or something like that is free to compute it correctly, even as it’s running on a physical computer that might be broken in a subtle way, possibly producing a different result. Identifying with an algorithm that your brain currently implements when making a decision doesn’t seem different, you are just a more complicated algorithm, producing some result. What the physical world does with that result is a separate issue, but for purposes of this argument the algorithm is selected to be in tune with the world, it’s an algorithm that the brain is currently simulating in detail.