Is there such a thing as objective reality?

[anvi]

Just because something isn't perceived doesn't lend warrant to the inference that it's unreal.  The fact that the world wouldn't be experienced by, say, human beings if human beings didn't exist does not imply with necessity that human beings' perceptions "created" the world.  In addition to that logical point, there is the added fact that much in the world we've discovered is real despite the circumstance that we can't immediately perceive those things, but need inferential techniques and instruments to detect them.  Among these are electrons, x-rays, radiation bombardment from outside our atmosphere...and even numbers; no one has ever seen, heard, smelled, tasted or touched the number 3, and yet we do a stupendous number of things successfully with it.  Berkeley's infamous equation of perception and existence is then one of the most notorious philosophical conflations ever made.  Perceiving something certainly helps lend great credibility to our belief in its existence, but that doesn't make the converse true; a failure to perceive something does not imply with necessity that it doesn't exist.

[anvi]

Well, there are lots of things at issue here. 

One is the way that the phrase "objective reality" has been applied.  It's supposed often to denote either "reality independent of the mind" or in some way reality as it would appear to a being who could know everything "as it is in itself."  But that conception of "objective reality," it seems clear, demands an impossible standard of knowing.  We can only experience and know the world as the kinds of beings we are.  But if some artificially perfect standard of objectivity is not and will never be attainable by us, that doesn't entail that we don't know anything about the world that we can justifiably suppose are natural facts. 

Another thing raised here are the limitations of our observational perspectives, and hence the limits of our descriptive capacities.  But I'd argue that the limits are not necessarily fixed in one place.  We can make decisions and cultivate habits that contract the limits of our observation and knowledge, but we can also do things to expand them. 

Finally, there is the observation that everything we think and say is the result of mental activity.  True enough, of course.  But human minds are not disembodied realms of abstraction; they are physical organs that are integrated with organs of sense and activity and locomotion, and they interact with an environment.  That means our thoughts, distinctions and language, while obviously mental constructions, can bear relations with the natural world and be informed by those relations. 

Idealism, most of the time, does not merely stop with making statements about the limits of our ideas and language, but reaches for metaphysical inferences about the world on the basis of these limitations.  I'm perfectly comfortable with the pointing out the limitations of human experience and knowledge.  But the idealist metaphysical implications of these, despite a previous fascination of mine with Kant, don't convince me anymore.  We are physical creatures living in a physical world, and our knowledge and language are flawed but often quite functional outgrowths of that situatedness, not walls that make nature utterly inaccessible to us.   

[anvi]

I'm not sure scientific breakthroughs have destroyed materialism.  The smallest elements of matter may be more energetic dynamics than "elements," and they may have a lot of "empty space," but that doesn't mean the compound things that they combine and accrete to make up aren't material.  Only an insistence on reductionist moves to the exclusion of everything else would call matter a 'mere abstraction."  What modern physics has killed, it seems to me, is a certain view of material mechanics that lended warrant to determinism, and that killing was correct.  I don't know many lab scientists who are trying to use logic to explain the world, but most of them still use mathematics, as well as various kinds of measurement, and all these are human-made techniques.