Neither Lucas' argument here, nor any other anti-materialist argument, has offered any hint of what is missing from the materialist position, so the absence of

Neither Lucas' argument here, nor any other anti-materialist argument, has offered any hint of what is missing from the materialist position, so the absence of adequate knowledge is at best symmetrical. It is not unscientific to speculate on how things may be - without that, there would be no hypotheses. Lucas's argument claims that materialism is false, so Udo is within his logical rights to assume otherwise -- it would be begging the question to insist he cannot do that. None of this makes any progress on the question of whether Lucas' argument is valid and sound.