Something which appears to be that which it is not.
A DeceptivePractice may be a deception of commission or omission.
- A deception of commission is one which overtly proclaims to be that which it is not.
- A deception of omission is one in which the true nature of something is concealed or hidden from view.
One of the worst features of deceptive practice is that it is generally a violation of the principle of simplicity. A deception is inevitably more complicated than the truth, for the simple fact that you have two things, the deception and the truth, where otherwise there would be one. In the words of AntoineDeSaintExupery:
You know you've achieved perfection in design, not when you have nothing more to add, but when you have nothing more to take away.
A parable: One of the more striking examples of deceptive practice I remember was a friend's stereo in college. This was a cheap unit, gussied up to look more expensive. It was a single integrated system, configured to look like a stackable component system. There were dual slider volume controls, which fail on several grounds. First, dials offer far better control (your fingers work better in opposition, as in a dial, than in linear motion, as in a slider. But the capper was that the two controls were actually fused -- there was only one volume control. Likewise, the "equalizer" appeared to be a six-band job when it was in reality just treble, midrange, and base, on similar fused slider controls. A piece of junk. Compare, by contrast, the hardware Bose puts out, which is minimalist in the extreme.
See also AvoidIllusion, SecurityByObscurity.