"Vi har olika definitioner av vad som är rättvist."

Translation: We have different definitions of what is fair.

[Vedun]

What does som make here? What's wrong with 'av vad är rättvist'?

[Lundgren8]

It’s a relativiser. You don’t use it in this English sentence, but it’s a relative clause so it’s literally ”what which is fair”. Think of it as ”that which is fair” but with ”what”.

[ouzun]

Can we say the same sentence with no "som"?

[Zmrzlina]

No, Swedish needs it.

[IanCaliban]

I'm going to struggle to remember to put that in.

[BettyJJ]

But "vad" is also a relativiser, isn't it? There is a sentence in the course "Ser du vad jag ser?" I don't understand why that sentence does not need "som" while this one needs "som". Is it because the "av" part in this sentence?

[MarvelMani1]

I think it works this way...
if vad introduces a subordinate clause and there is no other subject in that clause it must be followed by som . Same thing with vem and vilken.

Hon undrade vad som var bäst...She wondered what was best.

Hon undrade vad han ville... She wondered what he wanted.

Han frågade vem som ringde...He asked who called.

Han frågade vem hon ringde...He asked whom she called.

[pekarekr]

Does Swedish need "som" in this sentence to express "whatever," as in "vad som helst"? If so, why drop "helst"?

[InvertedGo]

No. It is not a shortening of "vad som helst".

[SheSpider]

I was marked wrong for "We have different definitions of what is right." with a correct suggestion of "We have different definitions of what is just." Not close enough?

[HelenCarlsson]

rättvist: http://sv.forvo.com/search-sv/r%C3%A4ttvist/

[roblnls]

alternate correct(?) "We have different definitions as to what is fair."

[ToranSharma]

Given that is sentence is in the science topic, can 'rättvis' mean fair in the probabilistic sense, like a fair coin or a fair die.

[Pump540951]

Can I say "Vi har olika definitioner om vad är rättvist."

[MarvelMani1]

I read in an old learn Swedish book that “ if vem, vilken or vad introduce a subordinate clause, and there is no other subject in that clause, they must be followed by som:
Han frågade vem som ringde. He asked who phoned.

Hon undrade vad som var bäst. She wondered what was best.

But

Han frågade vem hom ringde till. He asked whom she phoned.

Hon undrade vad han ville. She wondered what he wanted

[Pump540951]

No answer up to now?

[ToranSharma]

The question had already been answered above three years ago.

No, you need the som. I think the construction is similar to in English "that which", or less directly "what it is that is" instead of just what.

I.e. We have different definitions of that which is fair.

Vad & som seems to fairly nicely correspond with that & which respectively.

[OdileBlanv]

Andra wouldn't work instead of olika?

[espekia]

"definitions of fairness" isn't allowed?

[Zmrzlina]

That would be "definitioner av rättvisa". We want to keep the sentence structure.

[Metlieb]

Why is the som required here?

[Zmrzlina]

See Lundgren8's answer to Vedun above.