Rabbi
Moshe Chaim Luzzatto ("RaMChaL"):
138 Openings
of Wisdom
Opening 101
The head includes the crown - Keter - and the mental powers within it.
The head is always the beginning of the entire government of the Partzuf, and is only complete with the crown (Keter) and the mental powers (מוחין, mochin) within it - that is, through the mystery of the indwelling of the one above it, which rests upon it. Included in the head are the three mental powers of the Partzuf, because that is where the whole birth of the governmental order of the Partzuf in essence takes place.
We now come to a detailed explanation of the form of the Partzufim, starting with a general rule.
This proposition has two parts. Part 1: The head is always. This defines the Head of a Partzuf. Part 2: .that is, through the mystery. This explains the above premise.
Part 1: The head is always the beginning of the entire government of the Partzuf. The head itself includes everything that exists in the entire Partzuf - but in the form of a beginning (ראישית, reishit). This is why it is called the head (ראש, rosh), while the function of the head is then completed through all the rest of the Partzuf (see Opening 90).
.and is only complete with the crown (Keter) and the mental powers (מוחין, mochin) within it. These are two distinct aspects both of which are needed in order for the Partzuf to exercise its governmental power. The crown, Keter, is one kind while the mental powers are another.
Part 2: .that is, through the mystery of the indwelling of the one above it, which rests upon it. For there must be a superior power that governs the lower one, as distinct from the lower power itself in all its attributes. The crown, Keter, is the superior power. (Keter reflects the governmental mode of the Partzuf above).
Included in the head are the three mental powers of the Partzuf. These encompass all the attributes of the lower Partzuf. (The three mental powers contain the roots of the governmental power exercised by the lower Partzuf, because Chochmah-Binah-Daat are the roots of Chessed-Gevurah-Tiferet.)
.because that is where the whole birth of the governmental order of the Partzuf in essence takes place. It is through the ingathering of all these powers on the level of Chochmah-Binah-Daat that the government order of the Partzuf is born, and from the head it extends through the entire Partzuf.