It is not necessary to make an effort to think in a particular way. Your thinking should not be one-sided. We just think with our whole mind, and see things as they are without any effort. Just to see, and to be ready to see things with our whole mind, is zazen practice. If we are prepared for thinking, there is no need to make an effort to think. This is called mindfulness. Mindfulness is, at the same time, wisdom. By wisdom we do not mean some particular faculty or philosophy. It is the readiness of the mind that is wisdom.
Wisdom is not something to leam. Wisdom is something which will come out of your mindfulness. So the point is to be ready for observing things, and to be ready for thinking. This is called emptiness of your mind. Emptiness is nothing but the practice of zazen