Plato’s Imperfection Argument

Plato’s imperfection argument tries to prove two interesting claims. The first claim is that F’s exist. The variable ‘F’ here designates concepts such as Equality, Beauty, Justness, Piety, etc, which Socrates claims to be equivalent in regards to his argument at 75c-d. The second claim is that our souls exist before our birth. I’ve tried to take what is central to his argument, and present it in a pseudo-Fitch format.

Plato’s Imperfection Argument Notes

1. We can only think of things we have
experienced.

2. We have had senses since birth.
3. Our bodies did not exist before birth
4. The sight of one thing makes us recollect
another.
5. We are able to discern the degree to which an
object is F.


6. Suppose an arbitrary perceptible
object(s) exists
7. The object(s) appears to be F
8. It is not the case that the object(s) appears to be F
9. Absurd
10. The perceptible object(s) is/are imperfectly F

11. All perceptible objects are imperfectly F.

12. An object is F if and only if it is perfectly F.

13.. We are aware of this imperfection in
perceivable objects.

14. We perceive objects to be imperfectly F.
15. If we are aware that something is imperfectly
F, then we must know of a perfect F.


1. 75 (end of page 65). Note that experience here is sense perception.
2. Suppressed Premise
3. Suppressed Premise
4. 73d-e

5. 74-b. This is not an exact discernment. Also, this may only apply to recollected, similar objects.
6-10. 74b-c. This is an attempt to show why Socrates might think 11. Eleven may simply be a suppressed premise. If this is the case, then I’m not sure what to make of the “objects appear to be F and not-F part”.

11. Suppressed conclusion. Also, objects are limited to this-life objects. (6-10 All intro).
12. 74c-d. (Stipulation or an analytical consequence of F’s)
13. 74d-e. (11, 5 analytical consequence-abbreviated as AC from here on out.)
14. (13, Reiteration)
15. 74e This is either a suppressed premise or (5, AC –we can’t discern if we don’t know a perfect F because everything would be perfectly F)
16. We know that there is a perfect Fnot just that there is one, but that we know the F

17. There is such a thing as the F itself


18. F type things exist


19. Suppose F type things exist

20. Looking at objects that are imperfectly
F reminds us of F

21. We can only think of things we have experienced.
22, If we can think of F, then we must have
experienced it at some time.
23. We haven’t experienced F after birth.


24. We experienced F before our birth.

25. Our bodies did not exist before birth

26. Something identical to us, but not our
body, that is able to sense (since it can
know things) exists.I don’t think he’ll want to say that our soul senses, though. I would rephrase this premise.
27. Call this thing the soul.



28. The soul sensed F before our life














16. (15, 13 If elimination)

17. (1, 16 AC) Alternatively, a Parmenidian principle may be in play.
18. (17, Existential introduction) Alternate phrasing is “some things are F’s”


20. (4, 19 AC) or (4, 14, 15 AC)this step doesn’t seem to be required


21. (1, Reiteration)

22. 75 (21, 20 AC)it doesn’t appear that you need step 20 to get this. All you need is step 21.

23. 75b-c (11,1, 12 AC?) Everything is imperfectly F, so no after birth experience of F.you might want to include this claim in the main argument as a set of steps. You’ll also need some claim about that which we experience after birth (in addition to 1, 11, and 12)
24. 75c (23, 21 AC)-Sketchy move?
25. (3, Reiteration) –Remember, this is a suppressed premise.
26. Suppressed conclusion
(24, 25, 1 AC)

27. Suppressed conclusion. Stipulation on 26, I’m just naming the theoretical thing.

28. 76c-d. Socrates replies to two objections to this premise here. The first is that we don’t seem to know everything. The second is the possibility we gained this knowledge at birth. The objections and responses do not play a role in the argument I’m outlining and will not be considered here.





29. The soul exists before our birth.

30. If F type things exist, then our souls exist
before our birth.

30(a) If F type things exist, then our souls exist
before we are born and F things exist in the
pre-birth realm.

31. F type things exist.

32. Our souls exist before we are born.

32(a) F things exist in the pre-birth realm






29. (27, 24, 25 AC)

30. 76d-77 (19-29, If intro)


30(a) Alternate stronger conclusion. F things exist to be sensed pre-birth, so Socrates could add this.
31. 77 (18, reiteration)

32. 77 (30, 31, If elimination)

32(a) Same as above, but suppressed



My objection to Plato:
Plato’s argument seems weakest at steps twenty-four. In step twenty-four, Plato seems to resolve the paradox created by his claim “we can only think of things we have experienced”, and the fact that we have knowledge of perfect entities (Justice, Equality, etc.) that we haven’t encountered in our lives by concluding that we must have encountered the perfect entities before we were born. Plato could have alternatively concluded from the absurdity that it is not the case that we can only think of things that we have experienced, or that we don’t really have knowledge of perfect entities. Concluding that we encounter the perfect entities before we are born introduces more problems that need to be explained, such as the existence of a soul, the soul’s location before birth, and the apparent divide between the perfect entity’s pre-birth location and real-life manifestations of them. I think that Plato should have appealed to a simpler explanation in resolving the paradox, and not have concluded that we encounter perfect entities pre-birth.

Works Cited
This webpage was helpful: http://faculty.washington.edu/smcohen/320/phaedo.htm#imperf