Answer:
Your question is pretty ambiguous. First of all, the natural logarithm is a function and requires a variable to be input into it. Secondly, the process of differentiation is a type of transformation or operation performed on a function, and it is done with respect to a particular variable. Its important when you ask questions in math that you ask a full, explicit question.
"How do you differentiate, with respect to x, the function ln(x)" would be more proper.
Or simply do it in math:
d/dx ln(x)
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The answer to the question is simple. It is 1/x.
d/dx ln(x) = 1/x