“In observing, we must remember a few more things:

When we are not able to see something,
It is either because something else is more obvious,
or because it is too close to us.
(Sāṃkhya Kārikā of Īśvara Kṛṣṇa Āryā Seven)

We can only observe when there is an inclination to do so.
(Yoga Sūtra Chapter Four verse 17)

Because of our own memories, backgrounds, cultures, etc.
Each person looks at the same problem differently,
which may cause problems.
(Yoga Sūtra Chapter Four verse 15)

We must respect time and change,
although the tendency nowadays is otherwise.
We must wait and observe more than once
so as not to be trapped by the fact
that things appear like this one day
and like that another day.”

– TKV Desikachar on Sāṃkhya and Yoga