I could say much the same about any text from any culture - but I think that's more or less a cop out.
As Carsten noted, it's not uncommon to for texts from many different cultural contexts to be read and studied, and nobody questions whether or not it's possible to correctly interpret them.
Translation of the word "Aiki" is not all that difficult, although it requires a certain background - but that background is available to anybody, Japanese or not.
Agreement on the translation is, on the other hand, another matter.
If anybody's interested here's some discussion of the definition of "Aiki"
. Before anybody goes nuts - no, it does not contain all implications of the word as ever used, it's just some general discussion.