To Verify or To Validate?

["Rollings, Gill" <WGILLR -at- WOK-MSMAIL-GW -dot- ISL -dot- COM>]

Marc Santacroce posed the question "What is the difference between
verification and validation?"  My first thought was that, according to the
way I read the terms being used:

* to verify is to check, e.g., by following instructions, that something is
true - it's a yes/no choice

* to validate is to check that the information offered is acceptable - this
may allow for a range of choices.

Then I took my trusty OED down from the shelf.  The first definition of
verification is "The action of demonstrating or proving to be true or
legitimate by means of evidence or testimony; formal assertion of truth.
 Now rare."  Further definitions are about testing experimentally the truth
of theories, assertions, etc.  So the legal undertone seems to have
disappeared over the centuries.  But the "proof" aspect is still there.

As for validation, it's the act of validating (!).  To validate is "To
render or declare legally valid; to confirm the validity of (an act,
contract, deed, etc.)....  To make valid or of good authority; to confirm,
corroborate, substantiate, support."  So, if you say it's true, it's true.

It looks as though the meanings of these words have altered subtly over the
years, as the definitions that I would recognise from the way people use
them are not the same as those offered by the OUP.  Still, I offer them for
what they're worth.

Gill Rollings, Technical Writer, Internet Systems Ltd
gill -dot- rollings -at- isl -dot- com