Facts are always true. In my analysis of the way things are, I have found that what we have is not necessarily relativism but rather a constant interaction between the personal (call it the holographic reference wave) and the holographic universe of events. Viewing concrete reality in this way provides a deeper understanding of the ways of the universe and a line inquiry well worth pursuing.
What we call facts are nothing more than a memory of some beliefs (it has all passed and therefore subject to have changed) which has been reinforced by a population with similar memories or beliefs (or other the of information such as a photograph), all of which is subject to re-examination and change. It is concrete and real - it is our memory - but it is also constantly changing because all of it is some passed event in memory.
It should be noted that no branch of science provides facts. Science provides measurements (observations) and predictions, that are approximations of some past or potential future event, that fall within necessary tolerances for some practical application. These predictions and formulas are reinforced by experiments but are subject to change when they fail in some application. Hence even science is subject to change based upon the same agreement or lack of agreement between observers in the scientific population.
Logic does lose its preeminence in this philosophical approach while the psychology of the mind and a new understanding of the way a holographically universe may operate rises.