Assuming you have the documentation, or assuming that you can extrapolate from a program in a language that you already know. If one knows python and is given

Assuming you have the documentation, or assuming that you can extrapolate from a program in a language that you already know. If one knows python and is given a program in APL, then likely an insurmountable barrier has been reached. If you don't have the docs the describe the language, the one can try to infer the language by running experiments on variations of the stored program. However one needs access to the processor in order to run different experiments and get different results to be able understand how the programming language works. We don't have CPU in a form that we can experiment with ("brains in a vat"). We have a 50Mb string in APL*2, a mostly unknown language for a mostly unknown processor. The other part is that this is not a program but a meta-program -- meaning there are multiple levels of indirection. The DNA does not directly specify the brain, but instead specifies rules for components that would eventually arrive at an assembly (guided by a rich context of voluminous other inputs over an extended period of time) that constitutes a brain.