What is wisdom? How to contemplate? There are 4 aspects  of satipatthana meditation. Can anyone explain how  to do the cittanupassana? Is it not merelly noting the hate, greed and delusion? Isn't it?.
Many people will disagree with my answer because they wish to believe they are practising cittanupassana.
The word &quot;anupassana&quot; means to &quot;watch closely&quot; therefore cittanupassana is not &quot;noting&quot; because noting is thinking rather than watching.
Also, because &quot;anupassana&quot; means to &quot;watch closely&quot;, there is no thinking whatsoever in the mind when cittanupassana occurs.
For example, in the practise of Anapanasati, cittanupassana is practised with full concentration, i.e., with knowing each in-breath &amp; each out-breath.
About cittanupassana in Anapanasati, the Buddha commented:

I do not say that there is the development of mindfulness of breathing for one who is forgetful, who is not fully aware.
MN 118

Cittanupassana occurs after the breathing has calmed &amp; after the rapture that arises from calming breathing is also calmed.
Cittanupassana is directly knowing the quality &amp; purity of the mind. Although during cittanupassana the mind can have stains of greed, hatred &amp; delusions, these stains are not thoughts or thinking. They are the energy or mood of the stains/defilements themselves. Therefore, MN 10 says:

And how, monks, does a monk fare along contemplating mind in the mind?
Herein, monks, a monk knows intuitively the mind with attachment as a
mind with attachment;
he knows intuitively the mind without attachment, as a mind without
attachment;
he knows intuitively the mind with hatred, as a mind with hatred;
he knows intuitively the mind without hatred, as a mind without
hatred;
he knows intuitively the mind with confusion, as a mind with
confusion;
he knows intuitively the mind without confusion, as a mind without
confusion;
he knows intuitively the mind that is contracted, as a mind that is
contracted;
he knows intuitively the mind that is distracted, as a mind that is
distracted;
he knows intuitively the mind that has become great, as a mind that
has become great;
he knows intuitively the mind that has not become great, as a mind
that has not become great;
he knows intuitively the mind with (some other mental state) superior
to it, as a mind with (some other mental state) superior to it;
he knows intuitively the mind with no (other mental state) superior to
it, as a mind with no (other mental state) superior to it;
he knows intuitively the mind that is composed, as a mind that is
composed;
he knows intuitively the mind that is not composed, as a mind that is
not composed;
he knows intuitively the mind that is freed, as a mind that is freed;
he knows intuitively the mind that is not freed, as a mind that is not
freed.
MN 10