Learning by doing isn't the same thing as learning from books.

the 是定冠词，用于特指某个事物。 same 是形容词，意思是"相同的、一样的"。 thing 是名词，意思是"事物、东西"。 the same thing 是一个固定短语，意思是"同一件事物"，强调完全相同。