Facts

Although Joe Friday never really said it, “Just the facts ma’am” has become iconic ever since Dragnet appeared on Television in the Fifties.  So much so has our popular culture been enamored with the concept that ‘fact’ has, in many cases, become synonymous with ‘truth’.  This is an error which makes many think that ‘theory’ means ‘speculation’ and ‘fact’ means ‘verifiable truth’.  Our modern culture suffers from this confusion, and a lack of proper understanding of what the word ‘fact’ means.   The Philosopher, on the other hand, desires our speech to make sense, and therefore seeks clarity of thought. To further the discussion I offer these definitions:

A fact is an elemental datum of experience, or what is the case.

A fact is expressed by a proposition.

A proposition is expressed by a sentence.

A theory is a set of propositions which give us a scientific picture of reality.

A theory is expressed by a logically consistent set of sentences which adequately and accurately elaborate a theory. 

These definitions put together give us a linguistic-logical hierarchy and will help us understand the difference between ‘fact’ and ‘truth’.  A sentence is true if and only if it properly and accurately expresses a proposition.  A proposition is true if and only if it properly and accurately expresses a fact.  A fact is neither true nor false, it merely is.  The reader should note that our definition of ‘fact’ allows for both realist and idealist interpretations of data of experience.  A datum of experience could be merely an idea (percept, sense datum) in a person’s consciousness (idealism), or an experience of an object/event in the external (independent of consciousness) world (realism). 

The Realist holds to a correspondence theory of truth, whereby a proposition is true just in case it corresponds to an actual object/event in the world independent of a person’s experience (consciousness).  The Idealist holds to a coherence theory of truth, whereby a proposition is true just in case it is coheres (is consistent and fits) with all other known data of a person’s experience.

Theories are valid or invalid.  Theories are validated either by induction or deduction. A deductive argument validates a theory when the conclusion follows logically (with certainty) from premises known to be true, as in a Mathematical Proof.  An inductive argument validates a theory, by gathering evidence for the theory and assigning a probability to the expression of the theory.  Here the argument gives probable truth, but lacks absolute certainty of a deductive argument.  The deductive argument derives a conclusion by logic alone from premises known to be true.  The inductive argument starts with a hypothesis and gathers evidence to confirm or disconfirm the hypothesis.  Since it would be inconceivable to gather all possible evidence, the inductive argument can only give a probability measure of the hypothesis (a probable truth value), but if the probability measure is sufficiently high and we have gathered a large enough body of evidence, we generally consider the hypothesis or theory true.

So the next time the reader encounters someone who says that Evolution is merely (only) a theory, the reader should do as I do and respond: “True, but so is Gravity, and I am not about to leap off a ten story building to disconfirm the hypothesis that all objects fall towards the center of the earth.”