The first question:
Can the intellect be a door to enlightenment, or is enlightenment only achieved through surrender?
Enlightenment is always through surrender, but surrender is achieved through intelligence. Only idiots cannot surrender. To surrender you need great intelligence. To see the point of surrender is the climax of insight; to see the point that you are not separate from existence is the highest that intelligence can give to you.
There is no conflict between intelligence and surrender. Surrender is through intelligence, although when you surrender intelligence is also surrendered. Through surrender intellect commits a suicide. Seeing the futility of itself, seeing the absurdity of itself, seeing the anguish that it creates, it disappears. But it happens through intelligence. And especially in concern with Buddha, the path is of intelligence. The very word buddha means awakened intelligence.
In the Heart Sutra one-fourth of the words used mean intelligence. The word buddha means awake, bodhi means awakening, sambodhi means perfect awakening, abhisambuddha means the fully awake, bodhisattva means ready to become fully awake. All go back to the same root, budh, which means intelligence. The word buddhi, intellect, also comes from the same root. The root budh has many dimensions to it. There is no single English word that can translate it; it has many implications. It is very fluid and poetic. In no other language does any word like budh exist, with so many meanings. There are at least five meanings to the word budh.
The first is to awake, to wake oneself up, and to awaken others, to be awake. As such, it is opposed to being asleep, in the slumber of delusion from which the enlightened awakens as from a dream. That is the first meaning of intelligence, budh – to create an awakening in you.
Ordinarily man is asleep. Even while you think you are awake, you are not. Walking on the road, you are fully awake – in your mind. But looked at from the vision of a buddha, you are fast asleep, because a thousand and one dreams and thoughts are clamoring inside you. Your inner light is very clouded. It is a kind of sleep. Yes, your eyes are open, obviously, but people can walk in a dream, in sleep, with eyes open. And Buddha says: You are also walking in sleep – with eyes open.