Is there an external material world ? It appears that the skeptic can throw a spanner in the works at every turn: first by questioning the reality of an external, material world and if that doesn't stop the dogmatist who smugly offers proof of an external material world, by raising doubts about logic & rationality à la Agrippa and his trilemma! There's no way we could mount a defense against skepticism when it enters the arena on all thrusters with guns blazing.
:snicker:
That said, ignoring logical skepticism - that logic is inherently flawed - we could argue using principles such as the
novacula Occami. In a video titled
was the moon landing a hoax?, Niel deGrasse Tyson argues that it would far easier to land people on the moon than to create the illusion of doing so (can you imagine how many documents would have to be fabricated to prop up the lie not to mention how many stool pigeons Uncle Sam would have to pay to keep their mouths shut).
In short, in a weird and counterintuitive sense, an illusion is more complex than the real McCoy!