Even if they were different

[keannu]

I know "even if" is a presumption while "even though" is regarding a fact, but the underlined seems dubitable. If you say "Even though they were different",then the writer knows they were different for sure, but if you say "Even if they were different", it means the writer is not sure whether they were so much different, but just presuming it. Not necessarily? Is it an exceptional case?

ex)For half a century, from Picasso’s arrival in Paris in 1904 to Henri Matisse’s death in 1954, the two artists were not only rivals for the leadership of the international avant-garde but also each other’s greatest critic and fan. They could foster creativity through rivalry. Throughout history, there are many other talented contemporaries―Verdi and Wagner, Tolstoy and Dostoevsky, Gauguin and Van Gogh―who tested and taught one another, pushing each other to experiment in ways they might never have dared. Even if they were different in many aspects, the competition through rivalry inspired greater innovation.

[EyseBlaauw]

I'm not sure that your rule about presumption vs. fact is a hard one. I think the writer is just trying to suggest that there were differences.

[Tdol]

I would use though there, but I think you'll find that many people use them pretty much interchangeably. It seems sloppy to me.

[keannu]

I would use though there, but I think you'll find that many people use them pretty much interchangeably. It seems sloppy to me.

Wow!, this is a new finding!! I shouldn't tell my students the distinction between "even though" and "even if" is strict. I feel really ashamed of my teaching before.
My previous teaching below seems in vain.
1)Even if you are ugly, I will love you.=> I don't know if you are ugly or not
2)Even though you are ugly, I will love you.=> You are actually ugly.
3)Even if you were ugly, I would love you.=> You are actually pretty.

You mean 1, 2 are not that much distinguishable, so they seem to grasp the meanings just in context.

[keannu]

Oh, I was mistaken, 1 can be either accepted truth or predictive conditional, so in case of accepted truth, it's same as 2.
1)Even if you are ugly, I will love you.=> I don't know if you are ugly or not or I know you are ugly, but I will love you
Is it correct?

[5jj]

I don't know if you are ugly or not That reading is possible if you have become romantically involved with someone you have never seen - by correspondence, for example., It is possible that the person is ugly, but you will love them when you meet them in the future.

I know you are ugly, but I will love you. That reading is possible, but unlikely. 'Even though' would be the more natural choice. Even then, it is an unlikely thing to say ' "I know that you are ugly, but I will love you in the future".

[keannu]

I don't know if you are ugly or not That reading is possible if you have become romantically involved with someone you have never seen - by correspondence, for example., It is possible that the person is ugly, but you will love them when you meet them in the future.

I know you are ugly, but I will love you. That reading is possible, but unlikely. 'Even though' would be the more natural choice. Even then, it is an unlikely thing to say ' "I know that you are ugly, but I will love you in the future".

What do you mean by the underlined? If you say "Even though you are ugly, but I will love you" , it implies the underlined, that's what I meant, But you wouldn't say the underlined directly unless you are a crazy guy. Is that what you meant?

[5jj]

I did not say anything about 'crazy guy'. I simply think it is highly unlikely that I will ever be in a situation in which I tell someone:
1. I know that you are ugly;
2. Despite this knowledge, I will, in the future, love you.

I suppose that it is possible that one day I will meet a very ugly person and be struck by the thought that I will be smitten by them in the future. I'll let you know if it happens; don't hold your breath.