What of the tunguska event? For purpose of arguement, we'll assume that there was a person/sentient reindeer near the epicenter of the blast.
They're not looking up, so they don't see the comet (it was most likely a comet or other peice of lethal cosmic debris that our loving gawd left over from creation). It's entering the atmosphere at well above the speed of sound, so there's no way to here it. The person/reindeer's demise by incineration is far faster than their nerves can report, so even when they died, they have no idea what hit them, or in fact that anything hit them at all.
BTW, this is not an entirely unlikely situation, there were people near the impact site, and reindeer could be sentient (the reindeer are watching you!).
In the above situation, the poor sap was clearly unaware of any comet, before, during or after the impact. In fact, heisn't aware of anything after the impact, because he's just been turned into air pollution.
If the comet does not exist, because he's not aware of it and probably nobody else is and will only be tipped off by fallen timber and shock waves, then why is the fellow/reindeer so very dead?
If the comet did not fit into the definition of "existant" then please explain why all the trees are knocked over, when they were standing up yesterday, and why the windows are broken, and why the siesmologists have siddenly decided to study a-causal events.
The point is, there are no a-causal events on a macro scale. I'm not sure about a micro scale, quantum physics is not my thing, but conscienceness is definatly definable as being a macro scale. Neurons are pretty darned big compared to, say, neutrinos.
It is possible that an object, or event, goes unoticed by everyone, and is only detected later by subtle clues such as hundred-square mile craters and telephone-pole trees. Nobody saw the comet, but it, or something pretty darned close had to have been there or else this was an a-causal event, which never happen because they violate TLOP, and TLOP controls EVERYTHING controls EVERYTHING ELSE. I tend to reason that large zones where trees have been knocked over and windows shattered, with reports of a huge blast, are in fact caused by large explosions, and that large explosions, in keeping with everything we know about the world, are caused by something rather than non-existant entities, even if those entities cannot be observed.
Either this came down to a semantics brawl of the Franko pagent has just found a (two?) new contestant.
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How is it possible that his/her cells are affected by the viruses, but only after a certain point, when the the usual symptoms are felt and our patient counsiently realizes that he/she got infected (Sh!t, I´ve got the flu!) the infection becomes real?!