'on' or 'upon' ?

My intuition tells me they're both fine, and looking through several articles tends to support this. Many articles contain both variants (google both phrases and read a few texts).

Btw, in your context I'd personally prefer "choose" over either version.

If you want to go with "decide", I'd choose "upon" in this context, to avoid "on their own" which could trip a careless reader/skimmer.

If there's a difference in meaning between "decide on" and "decide upon", I'd be curious to hear about it, too.

You can do as you wish I guess. But, using choose instead of decide eliminates the use of either upon or on. But, if you keep decide you can use this to help I guess:

preposition:

1. up and on; upward so as to get or be on: He climbed upon his horse and rode off.
2. in an elevated position on: There is a television antenna upon every house in the neighborhood.
3. in or into complete or approximate contact with, as an attacker or an important or pressing occasion: The enemy was upon us and our soldiers had little time to escape. The Christmas holiday will soon be upon us and we have hardly begun to buy gifts. The time to take action is upon us.
4. immediately or very soon after: She went into mourning upon her husband's death.
5. on the occasion of: She was joyful upon seeing her child take his first steps.
6. on (in any of various senses, used as an equivalent of on with no added idea of ascent or elevation, and preferred in certain cases only for euphonic or metrical reasons): He swore upon his honor as a gentleman.

Good luck whatever you decide Donkey!

Christine

In case you decide to change the word "decide" here are a few synonyms you could consider:

adjudge, adjudicate, agree, arrive at conclusion, award, call shots, cast the die, choose, cinch, clinch, come to agreement, come to conclusion, come to decision, commit oneself, conclude, conjecture, decree, determine, draw a conclusion, elect, end, establish, figure, fix upon, form opinion, gather, go down line, guess, have final word, judge, make a decision, make up mind, mediate, opt, pick, poll, purpose, reach decision, resolve, rule, select, set, surmise, take a stand, tap, vote, will

Click to expand...

Also, the results for "choose."

accept, adopt, appoint, call for, cast, commit oneself, co-opt, crave, cull, decide on, designate, desire, determine, discriminate between, draw lots, elect, embrace, espouse, excerpt, extract, fancy, favor, feel disposed to, finger, fix on, glean, judge, love, make choice, make decision, make up one’s mind, name, opt for, predestine, prefer, see fit, separate, set aside, settle upon, sift out, single out, slot, sort, tab, tag, take, take up, tap, want, weigh, will, winnow, wish, wish for

Click to expand...

Thank you, thesaurus.com!

(Personally? I like "adopt" and "designate.")

I don't know if you ever consider your sentences metrically, but of the two options you initially presented, I prefer the rhythm of "upon," though both are correct. Meter could also influence your choice of a synonym.

Hey, Donkey, sorry I didn't see your post till now...

If you're asking about meter in particular, I' m not sure about source books for meter in the context of prose writing. My own approach to prose writing comes from a linguistics class I took called "discourse analysis" - which basically let me quantify a lot of the stuff I did already, and gave me greater control over it.

James Thurber (The Thirteen Clocks, The Wonderful O) is a very poetic writer, and so might give you examples of metrically interesting writing. I did have a discussion of it on my blog, too, entitled "Some thoughts on meter."

Another place you might look for inspiration and a new perspective is in the area of anthropology, which takes human cultures and examines them scientifically. I've taken a lot of inspiration from my own background in the subject.

I hope that gives you some ideas for where to go...