True Enough

TrueEnough is a special case of AlmostTrue, with a requirement that the extent of truth presented is GoodEnough.

Sometimes Truth, and nothing but the truth is not practical. The requirements of complete truth may overwhelm the audience, or the presenter of the material has not got all the facts, or there is not enough time, or ....

You can't handle the truth! -- from the movie A Few Good Men

What is needed for interhuman communications, in a busy world, is to communicate in a manner that is TrueEnough. Such is the case in IT project work, in the development and application of patterns, etc.

It is important that a TrueEnough interaction not be taken to a foreign situation out of context.

A StakeInTheQuicksand is TrueEnough for the time being to be a GoodEnough place to start.

A brief example: consider roller coasters. We can model their acceleration along the tracks by keeping track of the velocity of roller coaster as a tangent to the track - and let's not forget track friction and air resistance! Or, we could just use simple kinematic equations that only take the current height of the roller coaster into consideration, and ignore the facts that velocity is also dependent on friction, air resistance, and the amount of matter the roller coaster has relative to its speed and the speed of light (as explained by the Theory of Relativity).

The kinematic equations are just simpler - aka, they are just True Enough.

On the other hand, if you ignore some of these other things in trying to get a satellite into geosynchronous orbit, your satellite is doomed! In this case, Newton's equations aren't TrueEnough - we need the full power of GeneralRelativity.

You don't need GeneralRelativity for geosynchronous satellites. The speeds and gravitational fields involved are far too small for relativity to give different trajectories than Newtonian gravity. Now, GPS satellites need to take GeneralRelativity into account due to the precision required and the errors introduced as timing signals move from orbit to the Earth's surface due to the changing gravitional field (and thus changing time dilation). (Actually, GPS can work pretty fine without GeneralRelativity, with receivers calculating delta T between various satellites themselves. --AnonymousDonor)

[If the receivers use Newtonian mechanics, they will be off by 10km/day. Clearly, that's not good enough for GPS.]

CategoryCommunication