Philosophus dicit se non plane scire utrum fama vera sit.

Se is the reflexive pronoun, meaning himself/herself/themselves. In this sentence, it refers back to the subject of dicit, namely philosophus.

So Philosophus dicit se... means The philosopher says that he..., literally The philosopher says himself...

Latin uses se when the person inside the subordinate statement is the same as the subject of the main verb.

• Philosophus dicit se scire = The philosopher says that he knows
• Philosophus dicit eum scire = The philosopher says that he (someone else) knows

After verbs like dicit (says), Latin often uses an accusative-and-infinitive construction instead of a clause with that.

So English:

• The philosopher says that he does not fully know...

becomes Latin:

• Philosophus dicit se non plane scire...

Here:

• se = the subject of the reported statement, in the accusative
• scire = the infinitive verb

This is one of the most important Latin constructions for reported speech or thought.

It is called the accusative and infinitive construction, often abbreviated ACI.

In this construction:

• the subject of the subordinate statement goes into the accusative
• the verb of that subordinate statement goes into the infinitive

So:

• se = accusative subject
• scire = infinitive verb

Literally, Latin says something like:

• The philosopher says himself not fully to know...

But natural English is:

• The philosopher says that he does not fully know...

Plane means something like clearly, plainly, or completely.

So non plane scire means:

• not know clearly
• not fully know
• not quite know for sure

It does not usually mean a total lack of knowledge. It suggests uncertainty or incomplete certainty.

So the philosopher is not saying I know nothing about it, but rather I do not know for certain / I do not fully know.

In Latin, non often comes before the word it most directly modifies, or near the idea being negated. Here it negates the whole phrase plane scire: to know clearly / fully.

So non plane scire means:

• not clearly know
• not fully know

This is slightly different in nuance from simply negating scire as a bare idea. The point is not just not know, but not know clearly/completely.

Latin word order is flexible, so you may also see other arrangements in other sentences, but this placement is very natural.

Utrum introduces an indirect question, here meaning whether.

So:

• utrum fama vera sit = whether the report is true

This is not a direct question like:

• Is the report true?

Instead, it is embedded inside another statement:

• He does not fully know whether the report is true.

A useful way to recognize utrum is that it often introduces a yes/no question, either direct or indirect.

Sit is subjunctive because it is in an indirect question introduced by utrum.

In Latin, indirect questions normally take the subjunctive, even when English uses the indicative:

• utrum fama vera sit = whether the report is true

So although English says is, Latin uses sit, not est.

This is a standard rule:

• direct question: Utrum fama vera est? = Is the report true?
• indirect question: ...utrum fama vera sit = ...whether the report is true

Because the main verb is dicit, which is present tense. In sequence of tenses, a present main verb is a primary tense, so the subjunctive in the indirect question is normally a present subjunctive for action or time seen as contemporaneous.

So:

• dicit ... utrum fama vera sit = he says ... whether the report is true

If the main verb were past, Latin might use esset instead:

• dixit se non plane scire utrum fama vera esset
  = he said that he did not fully know whether the report was true

Vera agrees with fama, which is a feminine singular noun.

• fama = feminine singular
• vera = feminine singular adjective meaning true

Here vera is a predicate adjective with sit:

• fama vera sit = the report is true

So vera is not describing some other hidden noun; it simply agrees with fama.

Not in this sentence. Although fama can be related to fame/reputation, it often means report, rumor, or common talk.

Here utrum fama vera sit clearly means:

• whether the report/rumor is true

So this is not about celebrity or glory; it is about whether something people are saying is true.

Because Latin usually does not use a that-clause after verbs of saying, thinking, knowing, and perceiving in the way English does. Instead, it normally uses the accusative and infinitive construction.

English:

• The philosopher says that he does not fully know...

Latin:

• Philosophus dicit se non plane scire...

So if you are expecting a word like that, the answer is that Latin often expresses that idea structurally rather than with a separate word.

The word order is natural, but Latin word order is much freer than English word order.

This sentence is arranged as:

• Philosophus = subject
• dicit = main verb
• se non plane scire = reported statement
• utrum fama vera sit = indirect question depending on scire

A more literal breakdown is:

• The philosopher says
• that he does not fully know
• whether the report is true

Latin often places dependent ideas after the word they depend on, so utrum fama vera sit naturally follows scire.

Sometimes in English, yes. In many contexts, whether and if are both natural:

• He does not know whether the report is true
• He does not know if the report is true

But whether is often the more precise translation for utrum, especially in grammar explanations, because utrum specifically introduces an indirect yes/no question.

So whether is usually the safest choice when learning the structure.