Huang-Po said:
"This pure mind, which is the source of all things, shines forever with the radiance of its own perfection. But most people are not aware of it, and think that mind is just the faculty that sees, hears, feels, and knows. Blinded by their own sight, hearing, feeling, and knowing, they don't perceive the radiance of the source."
The source is the rationality... REASON itself, as compared with the personal "sight, hearing, feeling, and knowing" affectively.
In REASON there is no dualism, only what he called "clarity".
He also argued that perceiving the 'source' is to realise the essential fault of affectively categorising and conceptualising.... Clear logic and meditatively sourced rejection of affectively based concepts, was the route to clarity perceivable in the 'source'.
Reason shines with the radiance of its own perception. It does not 'judge', it does not 'love', it does not 'hate', it simply is essential clarity and logically incorruptible, having rejected all moral conceptualisations, seeing everything as what it IS.
Science ultimately seeks the source and objective truth of all things. It seeks the 'source' as surely as Huang-Po's personal techniques.