1. ¶1 - Review Ignore/reject the senses. Knowledge of myself:
I am a thinking thing
I doubt, affirm, understand, . . .
I have imagination-produced images and perceptual images (though the objects of the images might fail to exist, these modes of thinking do exist)

2. ¶2 – General rule Anything else?
Extracting a general rule from the cogito:
I know that I am a thinking thing.
This knowledge is based on a clear and distinct perception of its truth.
Clear and distinct perception couldn’t have yielded this knowledge if it were a fallible guide.
So clear and distinct perception is an infallible guide: it provides knowledge and guarantees truth.
[this is modeled on Hatfield, 2003]
“I now seem to be able to lay it down as a general rule that whatever I perceive very clearly and distinctly [to be true] is true”

3. ¶3 – Worry about the external world
Didn’t I perceive the way the external world is clearly and distinctly? And isn’t this less than certain?
This would raise a problem for the “general rule” about clear and distinct perception.
No, what I perceived clearly and distinctly was that I had ideas of things in the external world.
And I didn’t perceive clearly and distinctly that there really were external things resembling my ideas.
I simply thought I perceived this clearly, due to “habitual belief”

4. ¶4 – Simple truths and a deceiving God
But didn’t I perceive the truth of e.g. 2+3=5 clearly and distinctly? And isn’t it less certain?
When I focus on the power of God to deceive, it seems quite possible for me to be in error about these things.
But when I focus on the mathematical claims themselves, it seems entirely impossible for me to be in error.
[The force of the doubt seems to depend on whether I focus directly on individual truths, or whether instead I think of them generally, in a detached way.]
This ‘deceiving God’ doubt is very slight and “metaphysical” (or ‘purely academic’)
But I need to remove this doubt; otherwise, I can’t be certain about anything else.

5. ¶5 – Classification: Three types of thoughts
Thoughts: all the various kinds of mental items.
Idea: quasi-image that is of something, that represents something.
of a man, of a chimera, of the sky, of an angel, of God
Volition/emotion: idea + another factor
[other factor =? an attitude, or psychological force]
Judgment: idea + another factor
[other factor =? the attitude of thinking it true/false]
Volitions, emotions, and judgments contain ideas, and these ideas serve as their intentional object.
e.g., the object of desire, the object of fear, the thing willed or decided on, the thing accepted as true

6. ¶6 – Which thoughts can be false?
We want to avoid error, so we need to find out which thoughts can be false.
Ideas themselves can’t be false; no matter what they represent, I still have them.
Emotions and volitions can’t be false; no matter what attitude I have, I still have that attitude.
Judgments can be false.
Chief and common mistake: judging that my ideas resemble things in the external world.

7. ¶7 – Classification: Three types of ideas/origins
Ideas are of three types (depending on their origin):
innate: they are part of my nature
possible examples: what a thing is, what thought is, what truth is
adventitious: I receive them from encounters with the external world
possible examples: hearing a noise, seeing the sun, feeling the fire
invented: I use my imagination to construct them
possible examples: sirens, hippogriffs
Of course, I don’t yet know which ideas have which origin.

8. ¶8 – Arguments for idea-thing resemblance
Do I have any reasons to think that my apparently adventitious ideas resemble things in the external world?
Nature taught me to think this.
My ideas do not depend on my will; hence they don’t come from me, but rather from something else.
And it’s more obvious to think that a thing gives me an image of itself than some other sort of image.

9. ¶9 – Arguments: Problems with 1
“Nature... taught me to think this”
But there’s a big difference between “the natural light” and spontaneous natural impulses.
What the natural light reveals cannot be doubted.
There is no other faculty that is (i) more trustworthy than the natural light, and (ii) capable of disproving what the natural light reveals.
But spontaneous natural impulses have led me astray in matters of choosing the good; so why trust them more in matters of seeking truth?

10. ¶10 – Arguments: Problems with 2
“[T]hese ideas do not depend on my will”
But it doesn’t follow that I am not generating these ideas, or that they come from some outside source.
Perhaps they are being produced by “some other faculty not yet fully known to me”.
This has precedent: think of dreaming.

11. ¶11 – Arguments: Problems with 3
Surely they give me an image of themselves.
No, I’ve often found that my ideas fail to resemble the external things they represent.
Sun example:
I have two ideas of the sun.
One from my senses, and the other from doing astronomy.
Both can’t be right.
And reason persuades me the second is right and the first is wrong.
So even if my ideas come from external things, it doesn’t follow that they resemble them.

12. ¶12 – Arguments: Summing up
All three arguments fail.
So what makes me believe that “there exist things distinct from myself which transmit to me ideas or images of themselves through the sense organs or in some other way”?
Not reliable judgment, but blind impulse!

13. ¶13 – Another approach?
We’re still trying to find out whether any of my ideas come from something outside me.
Ideas as modes of thought are all the same.
All ideas are the same kind of thing: states of mind, mental contents, or something like that.
This provides no basis for knowing anything about their origins.
But ideas as representations are very different.
Some represent substances, some represent modes of substances. There are those that represent finite substances, and there is the idea of God.
Ideas that represent substances have more reality to them than ideas that represent modes of substances.
They have more objective reality. They have more reality in what they represent, or in their representational content.
[‘objective’ here relates to ‘object of thought, mental content’ and not ‘unbiased, mind-independent, existing in the real world’]

14. ¶14 – Causal principles
A cause must contain (at least) as much reality as its effect.
The cause of a stone must (in some sense) contain everything found in the stone.
The cause of fire must (in some sense) have as much perfection [reality?] as heat.
Likewise, the cause of an idea must contain (at least) as much reality as the idea contains.
More carefully, the cause of an idea must have at least as much formal reality as the idea has objective reality.
The cause of an idea of a stone must have as much formal reality as the idea has objective reality – that is, as much reality as the idea represents in the stone.
The formal reality of an idea is simply the reality of any mode of thought.
But the objective reality of an idea must be derived from a cause with just as much formal reality.

15. ¶15 – Quick objection
Objection: But why does an idea’s cause need to have formal reality? Why not just have as much objective reality as the idea has?
Reply: If the idea’s cause only had the objective reality (if the idea’s cause was just another idea), then we’d have to explain where it got its objective reality.
Eventually there has to be something with formal reality, that can put a stop to this backwards regress.
Conclusion: “Ideas... can easily fall short of the perfection of the things from which they are taken, but [they] cannot contain anything greater or more perfect”

16. ¶16 – Strategy for an argument
So here’s how I can figure out the origin of (at least some) ideas.
If I can find an idea whose objective reality is so great that it exceeds the reality I have in me, then I’ll know it came from something else.
I’ll know I’m not alone!
Otherwise, all I can know for sure is that I exist as a thinking thing, etc.

17. ¶17, 18 – List of ideas, first group
So here are my ideas: me
God
inanimate objects (corporeal things)
angels
animals
other humans
My ideas of angels, animals, and humans won’t help; I could have invented those ideas.
I could have easily constructed these ideas out of the other ideas (me, God, inanimate objects)

18. ¶19 – Ideas of corporeal things
What I perceive clearly and distinctly: size, extension, shape, position, . . .
Everything else: light, colors, smell, . . .
“I think of these only in a very confused and obscure way” [italics added]
These ideas might be false ideas
maybe not formally false, but materially false
they’re so unclear, I can’t tell whether they represent things or non-things, or whether they represent things as non-things

19. ¶20 – Confused ideas of corporeal things
These ideas don’t require an external source.
If they are false, then they arise from an imperfection in my nature
from nothing[!]
If they are true, then the reality they represent is so slight (I can’t even distinguish it from a non-thing) that they could have come from me.
no need to bring in something else

20. ¶21 – Clear ideas of corporeal things
Some of them I could have gotten directly from my idea of myself:
substance, duration, . . .
Others I could have gotten indirectly from myself:
extension, shape, . . .
these are just modes of a substance, so they might be contained in me eminently

21. ¶22 – Idea of God
But the idea of God? There’s no way that could have come from me.
“[A] substance that is infinite, <eternal, immutable>, independent, supremely intelligent, supremely powerful, and which created both myself and everything else (if anything else there be) that exists.”
All these attributes are ‘too much’.

22. ¶23, 24 – Infinity
I do have an idea of substance (from my idea of myself).
But not of an infinite substance.
Could have I gotten this from negating the idea of a finite substance?
No way!
Infinite substance has more reality than a finite substance, and hence my perception of the first must be prior to that of the second.
How could I know about some of my ‘lacking’ modes of thought (doubting, desiring), unless I already had the idea of a being without these defects?

23. ¶25 – Confused idea? Materially false?
Perhaps my idea of God is like my idea of heat, smell, color, etc. – confused, and perhaps even materially false.
Then it could have come from nothing.
Can’t be!
This idea is “utterly clear and distinct”
It has more objective reality than any other idea; hence it is the most ‘in itself’ true and least suspicious idea there is.
Though I do not “grasp” the infinite, I at least “understand” it and that is enough.

24. ¶26 – Am I godlike?
Perhaps the perfections I attribute to God are in me potentially.
After all, I’m learning right now, and perhaps this will increase to infinity.
If the perfections are in me potentially, then perhaps I have enough within me to generate the idea of these perfections.
[Then I wouldn’t need to bring in God to explain my idea of God]

25. ¶27 – Being godlike isn’t enough
Nope, even if I were godlike, it wouldn’t help.
My idea of God doesn’t contain potential perfections.
Constant increase in perfection would never reaches actual infinity; but God is supposed to be actually infinite.
An idea’s objective reality needs to be explained by actual being; potential being is (strictly speaking) nothing.

26. ¶28 – Switch to another version
I think that argument works.
But it’s hard to retain my conviction that an idea of a more perfect being requires a cause that actually is more perfect.
So I’ll try another version.
This time the question is: if God didn’t really exist, could I myself (with this idea) exist?

27. ¶29 – List of alternatives
So if I didn’t derive my existence from God, then whence or from whom?
Maybe from myself.
Maybe from my parents.
Maybe from beings less perfect than God.

28. ¶30 – From myself?
If I derived my existence from myself, then I am capable of creating something from nothing.
And if I could do that, then why haven’t I given myself total power, knowledge, etc.?
Surely the first is more difficult than the second.

29. ¶31, 32 – Beginningless past?
Did I always exist? If so, the same problem just given shows up.
If I always existed, then there has to be an explanation as to why I don’t go out of existence.
Preserving something’s existence from moment to moment is no different than creating it out of nothing.
So if I could keep myself in existence, then I could also create myself, and then the same problem shows up.
Do I have the power to keep myself in existence?
I certainly experience no such power; so I must depend on something else besides myself.
[This move looks highly suspicious]

30. ¶33, 34 – Someone else? If someone else produced me, it has to be God.
The cause must have as much reality as the effect; I am a thinking thing with an idea of God; hence my cause must be a thinking thing with the perfections of God.
If this thing caused itself, then it must be God.
If something else caused it, then eventually we arrive at God.
There can be no infinite regress here (especially because we don’t just mean prior and productive causes, but present and preservative causes)

31. ¶35 – Several partial causes?
Perhaps several partial causes produced me: the idea of one perfection from one cause, and of another perfection from another cause.
But the idea of God contains the attribute of unity.
And if something gave me unity, it also gave me the others; otherwise, I wouldn’t understand how the perfections connect to each other.

32. ¶36,37,38,39 – (Quick ending) 36: Parents? No way 37: Idea of God:
adventitious? no
invented? no
innate? yes
38: Unsurprising that God would implant an idea of God in me, as a “mark of the craftsman”; naturally, God can’t be a deceiver since deception is an imperfection.
39: Contemplation