The truth is that which is (considered to be) the supreme reality and to have the ultimate meaning and value of existence. Everything that’s around is can be considered the truth. Well, at least if you define it that way, a normal Newtonian Physical truth perhaps, whether or not modified or replaced by SR/GR but that's not the point. On the other end of the reality spectrum is the guess, or a prediction, assumption, presumption, or assessment of the truth (a result or an event) without sufficient information. Okay, Now, I did not consult any sources other than a dictionary to get this thread on the rails, just my own thoughts. Probably wrong, I could be undulated by philosophical quotes, but I would just get it straight how I think science ought to work and how it really works and what the consequences are of less scientific approaches (political induced for instance). So we want the find the truth and we start the attempt to finding with a guess. The logical hierarchy would be (working our way up): Guess: assessment without sufficient information Hypothesis: A tentative explanation for an observation, phenomenon, or scientific problem that can be tested by further investigation. Theory: A set of statements or principles based on empirical evidence and/or mathematical modelling, devised to explain facts or phenomena, especially those that has been repeatedly tested or is widely accepted and can be used to make predictions about natural phenomena. Law (physical or mathematical): A statement describing a relationship observed to be invariable between or among phenomena for all cases in which the specified conditions are met Fact: Something demonstrated to exist or known beyond dispute to have existed, or a real occurrence or event; Truth: the supreme reality. (used a dictionary but did some modifying) Now what I like to do with this thread is discussing the feasibility of this hierarchic model (I can see problems) and test it with regards to some well known accepted but especially unaccepted ideas in Earth science (my domain) like: “the great flood”, “global warming”, “the ice age”, “expanding world”, “Tectonics”, “pole shift”, etc. But we’ll see were we get.