I was thinking about the Prime Axiom- our assumption that our senses are not consistently lying to us when they report the external, objective world.
It occurred to me that we may not need the PA. We can hold our whole worldview, including the very foundations provided by our senses, tentatively- we need not posit an external world which our senses report with approximate accuracy. Instead of being an absolute, an axiom, the PA becomes a postulate. We don't presuppose it. We judge our worldview solely on internal consistency; we don't try to anchor it anywhere in any absolute, because there are no absolutes that we can perceive.
I'd like to explore this. Say we make no assumptions about the reliability of our senses, and start out theorizing that we are all solipsistic awarenesses. We, as sole observers, can still look for patterns, consistent and repetitious occurrences that impress themselves upon our consciousness. We can build up to an internally consistent system of apparent causes and effects, not grounded in anything but the necessary existence of our own consciousness. The existence of the external world becomes a powerful theoretical framework on which we- tentatively- build up our worldview, and remain open to the tiny possibility that we are in fact purely solipsist awarenesses. Thus, any evidence (defined as any consistent pattern within our awareness) which tends to deny the PA doesn't destroy all our theories of the physical (or better, metaphysical) world we observe- though it would necessitate a sea-change of worldview even deeper than the switch from classical to relativistic physics.
It may be said that then cogito, ergo sum becomes our presupposition; but I think that we can easily demonstrate that nihilism is the only alternative. I doubt even the most rabid theist will be willing to presuppose his own nonexistence!
...
I'm not a solipsist, partly because it appears that even when our senses fail us- drugs, injury, starvation, or optical illusion- the best explanation is still positing an objective universe outside of our sensorium. It's just that I can't absolutely prove that my experiences aren't solipsistic, and only *appear* as if the external world exists.
A hypothetical situation- suddenly, everyone on Earth can see infrared, as a directly visible color. No explanation for the change is found; all eyes simply have cones which pick up wavelengths below the red. The religious, of course, all start screaming "MIRACLE!!!". Science can give us no mechanism to understand the discontinuity.
Would we then accept that God *really did* do it? Well, I wouldn't and I doubt most of the philosophically sophisticated unbelievers here would, either. However, it *would* cause me to go back to my deepest beliefs, and reassess them all; since my very senses have changed in a profoundly unexplainable way, the Prime Axiom is out the window. If I were, say, an objectivist, my entire worldview might crumble. Aha, but if I had held the PA tentatively, as a postulate rather than a foundational axiom, I could comfortably retreat all the way back to solipsism, and rebuild from that point!
