That is where the good assistants come in. They launch the calculations. They occasionally terminate the calculations.
What you're talking about is not solving chess, not when "solve" is used in a technical sense. Not weakly solved or partially solved or softly... whatever adjective you want, it's not solving.
@6968
"understanding something on a conceptual level is completely different from making use of that concept in a programming language and even more so in a rigorous context such as solving chess."
++ That is where the good assistants come in. They launch the calculations. They occasionally terminate the calculations. The rule is not incorporated in Stockfish, the good assistants judiciously apply it to decide if Stockfish calculation is to be launched or not.
Let us see a few examples
1 e4 e5 2 Ba6?
1 e4 e5 2 Nf3 Nc6 3 Nxe5?
Is there material gain? Yes.
Is everything else the same? Yes, per judgement of the good assistants.
Conclusion: these are certain losses for white and do not need any calculation.
1 e4 e5 2 Nf3 Nc6 3 Bc4 Nf6 4 Ng5 d5 5 exd5 Na5
1 e4 e5 2 Nf3 Nc6 3 Bc4 Bc5 4 b4
Is there material gain? Yes.
Is everything else the same? No, there is some compensation that may or may not be sufficient.
Conclusion: calculate.
"Saying "we'll just program it to ignore bad moves" is intensely naive."
++ We do not change Stockfish, we use Stockfish like Schaeffer used Chinook for Checkers,
but the good assistants decide what to calculate and what not to calculate.