Matter possesses gravity in virtue of its tendency towards a central point. It is essentially composite; consisting of parts that exclude each other. It seeks its Unity; and therefore exhibits itself as self-destructive, as verging towards its opposite ... Spirit, on the contrary, may be defined as that which has its centre in itself. It has not a unity outside itself, but has already found it; it exists in and with itself. Matter has its essence out of itself; Spirit is self-contained existence (Bei-sich-selbst-seyn).