Concerning reality....

[Montrevux]

How does Objectivism justify that sensory perception is the foundation of knowledge?  How does an objectivist debate against the ideas of simulated realities? Or really, against any sort of idea that holds sensory perception is not the foundation to knowledge.

I say existence exists, but where do I get my justification for saying only this existence exists?

Perhaps this is to "matrix-like", but it is under my current realm of knowledge that one day in the future, highly specialized computers will be able to simulate everything from sight to touch. If we are able to create such realistic environments that someone would not be able to tell the difference between what is real and what isn't, how do we justify that what we hold as reality now is actually real?

[DavidOdden]

I say existence exists, but where do I get my justification for saying only this existence exists?

This is the really short answer: okay, go ahead and justify the claim that there is another, unknowable existence.

[D'kian]

This is the really short answer: okay, go ahead and justify the claim that there is another, unknowable existence.

Hear, hear!

BTW If there are such things as "alternate" or "parallel universes, they'd also be aprt of the existence which exists. Likewise, for those who bring up notions like telepathy or ESP, if humans are capable of telepathy (no evidence for that) then telepathy would be a sense like hearing or sight.

[JMeganSnow]

Perhaps this is to "matrix-like", but it is under my current realm of knowledge that one day in the future, highly specialized computers will be able to simulate everything from sight to touch. If we are able to create such realistic environments that someone would not be able to tell the difference between what is real and what isn't, how do we justify that what we hold as reality now is actually real?

This reminds me of something Leonard Peikoff says in OPAR (which you should read). So, the existence highly specialized computers that can simulate sensations are *given*, they can be taken as a foundation of knowledge, but the existence of rocks is conditional and debatable?

Do you have any *evidence* of the proposition that the things you see and hear are generated by a computer? If not, why even consider it? Do you go around worrying that your friends may have been replaced by imposters with no evidence of that fact? This is known as paranoia, and it's a mental *illness*.

[LaszloWalrus]

How does Objectivism justify that sensory perception is the foundation of knowledge?  How does an objectivist debate against the ideas of simulated realities? Or really, against any sort of idea that holds sensory perception is not the foundation to knowledge.

Try to construct an argument (even a bad one) without using any sensory material and without assuming that existence exists.

[hunterrose]

I say existence exists, but where do I get my justification for saying only this existence exists?

Like D'kian said, existence here is defined as everything that exists, so even unknown aspects of existence would still be included in the concept of existence - when they were discovered to exist in the first place.

How does Objectivism justify that sensory perception is the foundation of knowledge? How does an objectivist debate against the ideas ...that hold sensory perception is not the foundation to knowledge?

What would be the alternatives: 1) sensory perception is "important" but not fundamental to knowledge 2) sensory perception is immaterial to knowledge?

If we are able to create such realistic environments that someone would not be able to tell the difference between what is real and what isn't, how do we justify that what we hold as reality now is actually real?

If a computer were to simulate the sight, feel, and taste of ice cream through electrode stimulation, that would be a sensory perception. But what you have to remember is that this doesn't mean that the (simulated) ice cream exists. Just as seeing a stick bend when put in water doesn't mean that the stick is bending when put in water.