In history, if something arose independently, does that mean it was made from scratch?

Question

such as a writing system... if a countries writing sytstem arose indepednently did they invent it from scratch? or just tweak it from the next countries writing?

Answer 1

~Can't you tell by comparing the Cryillic Alphabet to Hieroglyphics, Sanskrit and the Latin alphabet that all written language came from a common source.  Of course, if you are a Christian, you understand that the entire world shared a common language, oral and written, until Yahweh or Jehovah or whatever name it was given at the time got ticked of at the Babylonian  architects.  That's why Polynesians have such abbreviated alphabets.  They really got the short end of the stick when the Tower came crashing down.

Answer 2

Either from scratch, or just without foreign influence.