Nobody writes precisely the same way. The concepts of handwriting identification are founded on fundamental scientific facts regarding writing. This theory allows document examiners to distinguish between authentic and fake writing and to identify the author of a sample of handwriting. The writing principle states that two people cannot write identically, even if they intend to. No two writers produce handwriting that is exactly the same. Even if you were to examine every letter an individual writer has ever put on paper, you would still be able to tell them apart because of differences in spelling, grammar, style, and punctuation. These differences result from factors such as age, gender, language, education, physical conditions (e.g., arthritis), and even personal feelings at the time they are writing. In addition, certain events can affect how someone writes including learning new things, copying someone else's handwriting, and having your handwriting analyzed by others. Even if two people claim to write exactly the same thing, their writings will not match up. The writing principle ensures that no two people write the same way, so it can be used to identify authors of samples of handwritten text. In conclusion, the writing principle states that nobody writes exactly the same way, which enables document examiners to distinguish evidence that was not intended for identification purposes.