grammar - にしても and としても, is there a difference?

にしても and としても...Don't they both have a meaning of "even if"? Is there any subtle difference between these two forms?

Answer

There is some overlapping meaning. There are also some differences.

I think you may be touching on the deeper subject of the differences between に and と.

Comparing the definitions of に and と shows that they can both be used to refer to the result（結果） of something. に shows the result of becoming (dynamic) and と shows the result of being (stative).

According to the 大辞林, the に in にしても is a form of the word なり which is a contraction of にあり and is related to なる.

The と in としても is a form of the word たり which is a contraction of てあり, showing completed action and is related to である.

にしても ⇒ になるとしても ⇒ になっても
としても ⇒ であるとしても ⇒ であっても

にしても implies "even when" something becomes the case

としても implies "even if" something is the case or "even as", "even for".

Obviously there is some overlap in English as well between "even when" and "even if" and I think that this generally agrees with the overlap in Japanese between にしても and としても.

So let's compare two sentences:

赤としても黒としても．．．事実は変わらない

（赤であっても黒であっても）

You could think of this as "even if it's red, even if it's black", which in context might give you something like this:

• "Whether it's red or black won't change the facts"

Or you could think of it as "even as red, even as black"...

• "Even as red or black, it wouldn't change the facts"

Or you could think of it as "even for red, even for black"...

• "The facts aren't going to change for red or black"

赤にしても黒にしても．．．事実は変わらない

（赤になっても黒になっても）

This could be thought of as "even when it's red, even when it's black".

In context, maybe something like this:

• "The facts won't change whether we make it red or black"

Or you could think of it as "even for red, even for black"...

• "The facts won't change for red or black"

However, using にしても I think it's difficult to get the meaning "even as" because while として implies taking on a role as something （医者として - "as a doctor"）, にして can't really fully express the idea of taking on a role.

Just as a final note, I think using the volitional ～しましょう makes the difference between に and と a little clearer.

赤にしましょう - Let's make it red

赤としましょう - Let's say that it's red