Indeed they are, including Harvard if you can get in. The secret is that an appropriate degree must be from an accredited institution so the credentials will be honored in the peer-reviewed journals, which is where science and philosophy are actually done and where they reside. An independent student can publish his own stuff on his own and go on Coast to hawk his work, but he will likely be bypassed forever by the credentialed historians, and then what would be the point?
The truth will be advanced wherever the fog is lifted.
Apothegmaticians agree that science is a search for the obvious.