The greatest of all, imo, is the invention of language. Language is the greatest of all because it's the only thing that made human knowledge transferrable and portable.

Without language, won't we be similar to other species?

And how about language, can it be considered an invention?
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Why not?
We obviously had it in us to invent language. Humans continue to consciously and deliberately invent languages. Math and music, for example. Computer languages and hypertext markup language.
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I agree
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If you put it that way, then yes. I agree!
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Came to comment exactly this.
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This one right here. Being able to pool knowledge among humans allowed everything else to happen.
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