Concepts change. This website is dedicated to showing how.
Why should such a site be necessary? Because the fact that concepts change has been strongly denied.
Dr. Leonard Peikoff originated the fallacy that concepts don’t change in his book “Objectivism the Philosophy of Ayn Rand”. He made his assertion on the grounds that our knowledge is held in the form of concepts and, if they varied, our knowledge would be unstable or incommunicable.