Socrates: Is one like person a friend to another like person inasmuch as the first is like the second?  And is such a person useful to the other man?  Actually, consider it this way: What help is able to be bestowed or what harm is able to be inflicted upon one like thing by another like thing? Or what could it undergo, which could not be undergone by itself?  Indeed, how could such things be mutually esteemed by each other, since they provide no aid to each other?  How is it so?

Lysis: It is not so.

ὁ ὅμοιος τῷ ὁμοίῳ καθ᾽ ὅσον ὅμοιος φίλος, καὶ ἔστιν χρήσιμος ὁ τοιοῦτος τῷ τοιούτῳ; μᾶλλον δὲ ὧδε: ὁτιοῦν ὅμοιον ὁτῳοῦν ὁμοίῳ τίνα ὠφελίαν ἔχειν ἢ τίνα βλάβην ἂν ποιῆσαι δύναιτο, ὃ μὴ καὶ αὐτὸ αὑτῷ; ἢ τί ἂν παθεῖν, ὃ μὴ καὶ ὑφ᾽αὑτοῦ πάθοι; τὰ δὴ τοιαῦτα πῶς ἂν ὑπ᾽ ἀλλήλων ἀγαπηθείη, μηδεμίαν ἐπικουρίαν ἀλλήλοις ἔχοντα; ἔστιν ὅπως;

οὐκ ἔστιν.

Lysis 214E-215A

Amongst the many definitions of friendship that have and will be dispensed with in this dialogue, Socrates here argues friendship cannot be based upon likeness.  The reasoning amounts to a practical objection:  If someone already possesses a trait or ability, any desire to duplicate this trait or ability is superfluous.

Socrates’ reasoning here seems to originate from certain analogies of ownership.  If I possess a cup of sugar, I have no need to be a friend to my neighbor to gain a cup of sugar.  Only in those cases where I lack a certain thing do I at all consider the possibility of becoming a friend to someone to gain that certain thing.  (I am unsure if Socrates would include here cases where the “thing” one is seeking is the person/friend himself, and not some intangible/tangible benefit given by the friend/person).

Nevertheless, although it may be true that the like person is not a friend with the like, this cannot be the case based on Socrates’ rationale.

Consider:

1.  To be similar is not to be identical:  In all the relevant ways, one cup of sugar is just as good as any other, as far as cooking goes.  In this functional sense, the cups are identical.  This is not the case with, for example, two people who are similarly skilled mechanics.  They each may know separately certain skills or tricks, which the other person does not.  At one and the same time, they both similarly know the mechanic’s art and they are able to help each other with certain tasks where their individual knowledge falters.  Thus they are friends based on similarity, but not identicality.

2.  Even if two people are identical with respect to a certain personality trait, or a particularly dominating characteristic, such as wisdom, there are still myriad imaginable ways in which they are different.  Two men might be professors of biology, and this will be the predominant characteristic in their lives.  But one might enjoy fencing; while the other uses his spare time to study yoga.  The later could benefit the former by offering exercises to heal an ailing back.  Again, mostly the same is not entirely the same.

3.  Also most of the “helps” and “harms” that a friend could provide are not of the either/or quality.  Being wise, helpful, caring, courageous, and a litany of other traits, are qualities that can diminish or increase, especially so in the context of a nurturing relationship.  So as a courageous person I could increase my courage by hanging around a similarly courageous person, and thereby both of us would benefit.  In this circumstance courage is not something we both “possess” as a product, but rather something we cultivate.

4.  Lastly, it could be argued that a “like” friend serves as a mirror.  He reflects all the good traits one has in oneself, but in the reflection of another one is able to see them more clearly, with greater delight, and from a more objective aspect.