¡Oye!,Chaparrito:

I conducted a "Google" search to see if there was any definitive translation for "Se parte de la base de que." I found the phrase to be often used and each time it seemed to translate O.K., given context, to "It assumes that" or maybe, "It presumes". But in every case and in context, that made sense.

The only down side risk, I think, is that it is "Google's" translator that is doing the conversion. In spite of that, as I said, contextually it worked every time.

Is this any help?

Moe

I think it literallly translates as "to get to the bottom of it".

I'm changing my guess

"Starting from the basis that"

Is this any help?

It sure is, Moe. At least I have confirmation that the phrase 'It assumes that' or 'It presumes that' is acceptable. Thanks!

However I would also love to have someone help me understand why it can be translated that way. I just can't figure out in my own head how to derive that from Spanish words in the phrase 'Se parte de la base de que...' I know 'base' could be 'basis', but...

Can anyone else chime in to help?

Thanks, mountaingirl!

That suggestion about the meaning 'to depart' got me going in a different direction. So I did some ‘thorough’ investigation. (Okay, actually I only talked to two native speakers, una Ecuatoriana, y un Español, but I think I understand!)

The word ‘parte’ in this expression is from partir and if you will look at definition #4 you will see: partir de -> to start from

Then there is the word base and definition #2 states: basis (fundamento, origen)

Therefore, ‘se parte de la base de que’ would break down into “it starts from the basis that...” Or as both links to the entries above put it: “It assumes that...”

What have we established? Ummm, that Google was right! And that (hopefully) I won't ever forget this expression. (That remains to be seen...)

Thanks to all of you for indulging my curiosity. I can be a bit weird that way.