Lfc, this is what does not make any sense to me. As i don't believe in constructivism, i avoid saying that perceptions play no role in creating a knowledge. Instead, I would simply say that perception (you believe what you perceive ) and knowledge are two different things. I, unlike you, think that knowledge or knowing true things makes a different in every body's life. If all people start believing that knowledge is constructed even when you perceived something as reality, what i think is that people will start believing in crazy crazy things like: a patient would believe that he got cured by a prayer instead of drugs, or whatever, for example. and the anarchy??? one extreme form of constructed (if one is to believe) "knowledge" is by a team of 23 world's renowned scientists on stem cell research led by a South Korean Hwang Woo-suk and published in the world's most renowned journal-- the Science (though i understand what is meant by "constructed" in phylosophical sense, i believe that this example also serves the purpose of how Bruno Latour discusses about knowledge construction). You can google this scandal if you want or you might be already well informed about it. Sorry for disturbing you, lfc. Thaha