conclusion — When you come to a conclusion, you decide that something is true after you have thought about it carefully and have considered all the relevant facts.
conjecture — A conjecture is a conclusion that is based on information that is not certain or complete.
generalisation — The formulation of general concepts from specific instances by abstracting common properties.
rationalization — to ascribe (one's acts, opinions, etc.) to causes that superficially seem reasonable and valid but that actually are unrelated to the true, possibly unconscious and often less creditable or agreeable causes.
reason — a basis or cause, as for some belief, action, fact, event, etc.: the reason for declaring war.