In this talk Thich Nhat Hanh said that Buddhism isn’t a philosophy but that it has philosophy in it. There is a minimum of knowledge of the world necessary in order to follow the Buddhist practice but after that we should get on with the practice and not dwell on philosophical speculation.
Thich Nhat Nanh talks about the much quoted Cula-Malunkyovada Sutta:
“Malunkyaputta, it’s not the case that when there is the view, ‘The cosmos is eternal,’ there is the living of the holy life. And it’s not the case that when there is the view, ‘The cosmos is not eternal,’ there is the living of the holy life. When there is the view, ‘The cosmos is eternal,’ and when there is the view, ‘The cosmos is not eternal,’ there is still the birth, there is the aging, there is the death, there is the sorrow, lamentation, pain, despair, & distress whose destruction I make known right in the here & now.”
In other words there are some things which we need to know and others we do not in order to practice. Philosophical speculation of this sort is simply not necessary.
This is what Thich Nhat Hanh means by saying Buddhism isn’t a philosophy. It is a practice after one comes to a conclusion about the nature of existence (that of impermanance, suffering and no-self). Philosophy, on the other hand, is still very much stuck in the question about what is its nature.