Therefore the actual being of ideas owns God as its cause, in so far as he is considered as a thinking thing, &c.

Q.E.D.
PROP.VI.

The modes of any given attribute are caused by God, in so far as he is considered through the attribute of which they are modes, and not in so far as he is considered through any other attribute.
Proof .-- Each attribute is conceived through itself, without any other (Part i., Prop.

x.); wherefore the modes of each attribute involve the conception of that attribute, but not of any other.

Thus (Part i., Ax.