The point of no return or the Rubicon is the point at which someone, or some group of people, must continue on their current course of action. Either they physically cannot turn back, or doing so would be too expensive or dangerous.
The term arises from aviation, where the point of no return is the point in the flight of an aircraft beyond which the remaining fuel will be insufficient for a return to the starting point. Supposing that an immediate landing is not possible because, say, the craft is crossing an ocean, having passed the point of no return means that the pilot must proceed forward in the direction of the planned destination unless they want to crash.
Points of no return arise because many actions are not reversible. If a developer decides to demolish a tower block to make way for a new stadium, the act of setting off the explosives is a point of no return. Once the tower block has been demolished, it cannot be undemolished.
Points of no return can arise because of sunk costs. Consider the act of travelling from Paris to Moscow by air. If the traveller decides to buy a non-refundable air ticket, then the cost of this ticket is now a sunk cost. If the traveller subsequently discovers that it would have been cheaper to travel by rail, she cannot take advantage of that new knowledge. Unless the traveller has plenty of disposable cash, she has passed the point of no return, and can only regret her earlier choice.
In human behaviour, in particular individual as well as collective decision-making, point of no return has become a popular metaphor denoting a stage in an undertaking, project, or the like, where the person or people involved are unwilling to stop and think about what they are doing. Rather, they hasten to continue on their chosen course of action. This false point of no return thus typically results in a real point of no return, and irrevocable commitment to the cause in question.
The flaw in the analogy concerns the inevitability of having to go on in the same direction. Whereas the pilot really has no sensible alternative to carrying on, generally humans at critical points in their lives are still free agents and thus do have the power to change their course of action. If they decide not to it may be because they are afraid of, and are trying to avoid, exposure, criticism, or ridicule. If you turn back to where you started, you admit that most of the things you have been doing since have been wrong. Accordingly, changing your mind and your course of action is the more difficult of the two options, even when that would be better. What is more, the farther you have already proceeded the more difficult it is to return. This phenomenon leads many people to believe that for them a complete change of course is impossible.
In Christianity, the notion of repentance also implies a reversal (metanoete) and future change of behaviour.
In its metaphorical sense, passing the point of no return can be used synonymously with crossing the Rubicon (see Rubicon)
See also:
Aviation
Causes
False Rubicons
