According to the article on transcendentalism, transcendentalists believed intuition was superior to sensory knowledge. explain why they thought humans could use intuition rather that their senses to gain ideas.

Transcendentalists did not accept the idea that the intellect had nothing that was previous to the experience of the senses. To them, there was a very important class of ideas which had nothing to do with experience. In fact, to them, it was through that specifically class of ideas that experience was gained.

Those were the intuition of the mind itself.

Transcendental, to them was not the same as transcendent. The intuition wasn't something something beyond human experience but something through which experience was made possible

because he was killed by the black arrow.