What Spinoza means in proposition 15 is that nothing can be created without God. Whatever we see, feel, or taste has been created directly or indirectly by God. There is only one substance in the universe and that is God or Nature; they are one and the same, and everything else is a mode or affection of God. Everything in existence comes from within God or is other words is created by God. God is the only being which is in itself and conceived through itself, and everything else is in it.
“By ‘Natura Naturans’ we must understand that which is in itself and is conceived through itself; that is … God in so far as he is considered a free cause. By ‘Natura Naturata’ I understand all that follows from the necessity of God’s nature…” (p.52). “Natura Naturans” literally means nature naturing and there is only one being which can be considered ‘Natura Naturans’ and that is God/Nature. Meaning, God is in itself and created through itself. In order for something to be regarded as that, it must be created through itself and not through something else. God is produced from in itself and for something to be considered ‘Natura Naturata’ it must be created through something else and not from itself .In other words everything except God is dependent of something in order to be created. God is considered a free cause because it is not dependent on anything and its actions are independent and free of any constraints. God’s action are not forced by anything, they are free.
“Nature has no fixed goal and … all final causes are but figments of the human imagination” (p.59). When speaking of Nature, we must understand it does not act with a final destination in mind. When Spinoza states “Nature has not fixed goals …” he means that nature is not out to get us and God isn’t punishing us through the means of nature. Nature’s actions pay no mind to us and are not directly caused to do us such harm or good. Nature is free and flowing it does meddle with the affairs of humans. For example, when a tornado rips through a farm and destroys everything in its path, from the barn to the crops it isn’t seeking revenge on the owner of the farm, nature wasn’t out to destroy that certain farm, it just so happened to be there. The farmer isn’t being punished by God through nature. Nature does not have a fixed goal.
“So perfection and imperfection are only modes of thinking” (p.153). When we say something is perfect of imperfect, it is only so from the way we are perceiving it. Everything in nature is perfect because it was created in that matter, it was created to be itself and being itself makes it perfect. Only the maker of the creation can know if what they created was the vision they had in their mind of perfect, so how can we say if one person is perfect when comparing him to another, when we do not know what the creator had in mind? When a newborn is different from the norm of society we quickly label them as abnormal, while not knowing that the newborn was supposed to conceived this way and it was not an error of nature. So the newborn who is imperfect in our eyes is actually perfect because nature created it so. So perfection and imperfection are just the ways we perceive things, what is imperfect in one person’s eye can be perfect in another’s and vice versa.