Why Peer Review?

Why is peer reviewing so important to be able to actually prove that your argument is indeed scientific. Anyone can claim something and then say it's scientific, it doesn't make it scientific.
Peer reviewing simply means that; at least one other scientist, not affiliated with you, with knowledge of the matter in question, has looked at the paper. After looking at your paper he/she has come to the conclusion that your facts seems real and plausible, and that your conclusions add up and actually makes sense considering the facts presented. There are a few key words in that are really important here, "other scientist", "not affiliated", "facts" and "add up". If someone does an inadvertent mistake, they won't usually see it themselves. The same foes for someone affiliated with you, because they may actually let you get away with a less thorough check; or in cases of pseudosciences like "The dangers of Dihydrogen monoxide", the scientist affiliated with you may be a practitioner of the same pseudoscience and willing to present the same false facts.

I am not going to be very demanding, present one paper that has gone trough a scrutiny process by someone with knowledge of the subject in question, and in their official capacity approved it as "not pulled straight out of the authors butt". However I will demand a three party relationship, author, publisher and reviewer need to be from separate institutions, and not directly affiliated; in very short terms, it means that none of the three parties can have an "office right down the hall" from any of the other parties. And for the record, home offices are not a way to circumvent this, use common sense.