You're missing the fundamental part about empirical testing.

In the slightly paraphrased words of Dara O'Briain: "Science knows it doesn't know everything, but that doesn't mean you can just 'fill in the gaps' with whatever comes to mind". Claiming that we couldn't recognise an advanced description of our world doesn't mean you can then jump in and say "... and so it's this!".

Likewise, if you were to hand Isaac Newton a paragraph explaining general relativity, something beyond his ability to measure even if he could conceptualise it, there would be no point applying Occam's Razor, because it's not describing something he can detect in the first place.