I often have heard arguments claiming that complete freedom of speech could lead to dangerous situations. Without complete freedom of speech, we hardly are living in a free society.
Which word would best link these sentences?
The first sentence introduces an argument against complete freedom of speech. The second sentence makes an argument in favor of it. The second sentence contradicts the first one, so the two sentences should be linked with the adverb “however.” “Therefore” and “so” would be used only if the sentences supported each other.