Only the wise know this mind, this mind called dharma-nature, this mind called liberation. Neither life nor death can restrain this mind. Nothing can. It's also called the unstoppable, the incomprehensible, the sacred self, the immortal, the great sage. Its names vary but not its essence. 
To enter by reason means to realize the essence through instruction and to believe that all living things share the same true nature, which isn't apparent because it is shrouded by sensation and delusion. 