Learn Hardcore Icelandic: Mér finnst frelsi til að elska þann sem maður vill mjög mikilvægt. - I think freedom to love whoever one wants is very important.

finna = to find, to feel, to sense
- e.g. Ég finn kuldann. – I feel the cold.
finnast (middle voice) = to seem, to feel (to someone)
- e.g. Mér finnst þetta gott. – I find this good / This seems good to me.

In your sentence we have mér finnst, which literally means “to me seems …”.

Because finnast works like “to seem to someone”, the person is in the dative case:

mér (to me) – dative of ég
þér (to you) – dative of þú
honum, henni, okkur, ykkur, þeim, etc.

So:

Mér finnst þetta mikilvægt. – I think / I feel this is important.
Saying Ég finnst is ungrammatical.
Ég finn would mean I feel / I find in a physical or concrete sense, not I think or it seems to me.

What exactly does mér mean here, and why is it in that form?

Mér is the dative singular form of the pronoun ég (I).

Rough declension of ég:

Nominative: ég – I
Accusative: mig – me (direct object)
Dative: mér – to me / for me
Genitive: mín – of me / my (rare as a pronoun)

The verb finnast takes a dative experiencer: someone to whom something seems a certain way. So we must use mér, not ég:

Mér finnst þetta gott. – This seems good to me.
Þér finnst þetta gott. – This seems good to you.

Why is mikilvægt in the neuter form? What is it agreeing with?

Mikilvægt is the neuter singular nominative form of the adjective mikilvægur (important).

In sentences with mér finnst, the “real subject” is often a clause or an idea, which is treated grammatically as neuter singular. So the adjective normally appears in neuter singular as well, even if the noun it’s about is not neuter.

Here, the idea is:

frelsi til að elska þann sem maður vill
the freedom to love whoever one wants

That whole idea is what “seems important to me”. Icelandic tends to use neuter singular for such abstract, clausal subjects:

Mér finnst þetta mikilvægt. – I think this is important.
Mér finnst frelsi til að elska þann sem maður vill mjög mikilvægt.

So mikilvægt is agreeing with the whole clause/idea, understood as neuter singular, not directly just with frelsi (which is also neuter, but the pattern would be the same even if the noun were another gender).

What does the structure frelsi til að + infinitive mean exactly? Why do we need til?

Frelsi means “freedom”. Often, Icelandic expresses freedom to do something as:

frelsi til að + infinitive
freedom to do X

Here:

frelsi – freedom
til – a preposition meaning to / for / towards, often marking purpose or goal
að elska – to love (infinitive)

So frelsi til að elska literally is:

freedom for to love → idiomatically: freedom to love

You normally do need the til in this pattern:

frelsi til að tala – freedom to speak
frelsi til að velja – freedom to choose

Saying just frelsi að elska would sound wrong; the til is part of the standard construction.

Why is there no article before frelsi? Could I say frelsið instead?

Frelsi is an abstract noun (freedom), and in Icelandic abstract nouns often appear without the article when you mean them in a general sense:

Frelsi er mikilvægt. – Freedom is important.
Kærleikur skiptir máli. – Love matters.

In your sentence, we are talking about freedom in general, so frelsi without the article is natural.

You could say frelsið til að elska þann sem maður vill, but that would sound more like:

the (particular) freedom to love whoever one wants

For a general principle or value, bare “frelsi” is more idiomatic.

What is the role of þann in elska þann sem maður vill? Why do we need it?

Þann is the masculine accusative singular of the demonstrative pronoun sá (that one).

In elska þann sem maður vill, it functions roughly like “the one” / “the person” and is the object of the verb elska:

að elska þann – to love that one / that person
sem maður vill – whom one wants

So the structure is:

að elska [þann] [sem maður vill]
to love [the one] [whom one wants]

Without þann, you’d just have sem maður vill hanging there, with no explicit object. Icelandic normally likes to have an explicit antecedent (like that one / the one) before sem in this type of relative clause.

A closer English-like gloss would be:

freedom to love the person whom one wants
þann = the person/the one

Could we just say elska þann sem maður vill without sem, or is sem necessary?

Here sem is necessary.

Sem is a relative pronoun, like “who / whom / that” in English. It introduces the relative clause sem maður vill (whom one wants), which gives more information about þann.

þann – that one / the person
sem maður vill – whom one wants

Together: þann sem maður vill – the one whom one wants.

Leaving out sem (→ þann maður vill) would be ungrammatical in this construction.

Why is it maður vill and not ég vil here? What does maður mean?

Maður in this context is not the normal noun man. It’s an indefinite pronoun meaning “one / you / people in general”.

So:

maður vill ≈ one wants / you want / people want

The sentence is talking about a general principle: the freedom to love whoever one wants, not just who I want personally.

Compare:

Ég vil – I want (specific person)
Maður vill – one wants / you (in general) want (generic)

English sometimes uses “one”, or more commonly a generic “you”:

the freedom to love whoever you want (generic you)
the freedom to love whomever one wants

Grammar-wise, is maður here in any special case? Does it change form?

In maður vill, maður is in the nominative singular, acting as the subject of vill (wants).

When used as this generic pronoun, maður:

is singular in form
takes a 3rd person singular verb (like vill, getur, gerir, etc.)

It does decline in other cases, but in its generic “one” use, you usually see it in nominative:

Maður vill vera frjáls. – One wants to be free.
Maður getur ekki vitað allt. – One can’t know everything.

Why is it að elska and not something like að elskað or another verb form?

After til að, you use the bare infinitive form of the verb:

að elska – to love
að tala – to speak
að velja – to choose

Icelandic doesn’t add anything like English “-ing” here; you just use að + infinitive.

frelsi til að elska – freedom to love
tækifæri til að læra – opportunity to learn

Elskað is a different form (past participle, loved) and would not fit here.

Could the word order be Mér finnst frelsi til að elska þann sem maður vill mjög mikilvægt or must mjög mikilvægt come right after vill?

The given sentence is:

Mér finnst frelsi til að elska þann sem maður vill mjög mikilvægt.

This word order is fine and natural: the whole phrase frelsi til að elska þann sem maður vill is treated as one big idea, and then it’s described as mjög mikilvægt.

You could also move the adverbial part for emphasis, for example:

Mér finnst mjög mikilvægt frelsi til að elska þann sem maður vill.
Mjög mikilvægt finnst mér frelsi til að elska þann sem maður vill.

These are grammatical but slightly different in emphasis and rhythm. The original version is very normal and perhaps the most neutral.

Is mjög always used like “very”? Can it modify adjectives like mikilvægt directly?

Yes. Mjög is a common adverb meaning “very”, and it directly modifies adjectives and some adverbs:

mjög mikilvægt – very important
mjög gott – very good
mjög fallegt – very beautiful

So mjög mikilvægt is simply “very important”, with mjög modifying the adjective mikilvægt.

Can I say the same idea with ég held instead of mér finnst? Would that change the meaning?

You can express a similar idea with ég held, but there’s a slight nuance difference:

Mér finnst frelsi til að elska þann sem maður vill mjög mikilvægt.
– To me, the freedom to love whoever one wants feels/comes across as very important.
(more about personal feeling/opinion, often a bit softer)
Ég held að frelsi til að elska þann sem maður vill sé mjög mikilvægt.
– I think that the freedom to love whoever one wants is very important.
(more like a stated belief or opinion, uses subjunctive: sé)

Both are natural. Mér finnst is extremely common and slightly more subjective/“how it feels to me”; ég held að … sé feels a bit more like reasoned opinion / belief.