This information is elswhere in the blog, but I wanted to have a handy standalone reference sheet. The arguments of classical theism conclude with something that is "pure actuality". That is, something with no potentials for change. What are the attributes of pure actuality?
Matter and energy can both change location, change configuration, come together, break apart, and so on. So they have all kinds of potential to change. Something that is pure actuality, with no potentials, must therefore be immaterial.
Having a spacial location means being movable, or having parts that are actually located over here but not actually located over there. Something that is pure actuality, with no potentials, cannot move or change or have parts that are non actual. Therefore, pure actuality is spaceless.
If subject to the effects of time, it would have the potential to get older than it was. But since it has no potentials, it has no potential to get older. Therefore, pure actuality is timeless.
If there is a distinction between two things, that means one has something that the other lacks. But pure actuality does not have potentials, and therefore lacks nothing. So pure actuality is singular. There is only one such thing.
The above are the negative attributes. Now for the postive attributes. They must be maxed out, because if the are not, then it would lack something and so just wouldn't be pure actuality in the first place:
Pure actuality is the source of all change. Anything that happens is a change. Therefore, anything that ever happens or could happen is caused by pure actuality. So pure actuality is capable of doing anything and is therefore all-powerful.
The ability to know something means having the form of that thing in your mind. For example, when you think about an elephant, the form of an elephant is in your mind. But when matter is conjoined with form, it becomes that object. Matter conjoined with the form of an elephant is an actual elephant. But when a mind thinks about elephants, it does not turn into an elephant. Therefore, being able to have knowledge means being free from matter to a degree. Pure actuality, being immaterial, is completely free from matter, and therefore has complete knowledge.
Also, "ignorance" is not a positive reality of its own, but rather is a lack of knowledge and hence an unrealized potential. So the thing with no potentials is all-knowing. NOTE: This attribute, being the more contentious one, is expanded upon here.
We can say that a thing is "good", not in the sense of being "something we personally like" (you may think a good pizza has anchovies, whereas others may not), but in the sense of being a better example of what it is supposed to be. When that thing better exemplifies its perfect archetype. For example, an elephant that takes care of its young, has all four legs, ears, and trunk is "good", or closer to "good", in the sense we mean here. If the elephant lacks something, such as a leg, or one of it's ears, it would not be as "good" as it would be if it had both ears. Since pure actuality has no potentials, it lacks nothing, and is therefore all-good.
An intellect naturally desires what it comprehends as good, and since we have shown above that pure actuality has intellect, then it also has will. It aims at the good, and the ultimate good is pure actuality, so it tends towards itself.
"Love" is when someone wills good for something. Since pure actuality willfully sustains everything in existence, and existence is itself good (in the sense meant above), then it wills good for everything that exists, and so is all-loving.
Consider how you can have a conversation with yourself. You talk to yourself as if it were another person: "Self, what are we gonna do today?!" and your other self answers, "Try to take over the world!" When you do this, there is in a way two people having a conversation, even though you are just one person. But as we showed above, pure actuality thinks about itself, thus creating its own twofold nature: thinker and thing being thought (itself).
Pure actuality, being all loving, also loves itself. This again creates a twofold nature: the lover, and the beloved (itself). Again creating a twofold nature.
Put both together, and pure actuality thinks about itself, and loves itself. So there is pure actuality, pure actuality as object of thought, and pure actuality as object of lover. Thus creating a trinitarian nature.