What does "if anything" mean?

Question

Suppose you work in a library, checking people's books as they leave, and a friend asks you to let him smuggle out a hard-to-find reference work that he wants to own. You might hesitate to agree for various reasons. You might be afraid that he'll be caught, and that both you and he will then get into trouble. You might want the book to stay in the library so that you can consult it yourself. But you may also think that what he proposes is wrong -- that he shouldn't do it and you shouldn't help him. If you think that, what does it mean, and what, if anything, makes it true?

What does it all mean? Thomas Nagel, Chapter 7

What does "if anything" mean in the context? Thanks

Answer 1

It means that there may not be anything that makes it true.

In general, "if anything" is inserted as a subordinate clause in a question about what things are in some way available, to acknowledge the possibility that nothing may be available.

Another way to put this particular sentence (though not a better way - the original is good) might be:

Does anything make it true? If so (if anything makes it true), what (what thing(s))?