Depends on how you define "I" or "my", There is a thread going about it.

First of all, it seems that thoughts just appear out of nowhere — clemogo

That is, you are at the mercy of your thoughts! The above statement came from a thought that appeared out of nowhere. In fact, you had no control in posting this topic! All of this has just appeared out of nowhere ...

Your ideas are yours, and nobody can take them away from you.

It does not matter that they had been sourced form elsewhere (if they had.) Your money is your money, despite the fact you did not make it.

Another way to look at it is that people like to have others to agree with their ideas. Whether they are good ideas or not, and also whether they are their own original ideas or not. Hence, proselyzation.

There is also civic, or secular, proselization, outside of atheistic dogma. There is, for instance, political correctness. They reform the speech, in the hope to reform the thought. Political correctness is highly unpopular, and I say not only because it wishes and endeavours to alter people's values, but also because the decree comes from humans, not form a deity. Deities have the right, in the esteem of most humans, to interfere with human nature; other humans don't have the right to get inside your head and shape your thoughts and values.

From my personal point of view, when I have a good idea, I like to take the praise for it; when I have a bad idea, I work it into a joke (but nobody ever laughs); and when I have no idea, that's how I spend most of my life.

The illusion of ownership is a bubble that is easily popped by the simple act of dying! What happens to my body, my thoughts, or my money when I’m dead, proves it never really was mine. If it were, I’d take it with me.

Intellectual Property Rights? :chin:

After 30 or so years, the stipulated shelf life of an idea, when it's been milked dry, every penny squeezed out of it, it enters the public domain.

What happens to my body, my thoughts, or my money when I’m dead, proves it never really was mine. — Present awareness

The way I look at it, those things are mine while I'm alive. When I'm dead, they cease to be, true, but that does not prove at all that they were not mine while they were mine.

There is no permanence, true. But temporary ownership IS ownership.

To the extent that you don't share or speak about your idea at all, then they belong solely to you.

As soon as you express it though and another person hears it, you'll be stuck with the problem of not knowing if your idea was tainted by another persons idea, which you forgot about, or absorbed indirectly. Most of the time, even when you do think you have a unique idea, then you realize someone else said it long ago, often (but not always) better than you did.

The really interesting issue, the really mysterious one, is a persons first idea. That one comes from within. The only "learned" thing here is the word you use, not the idea. Innate knowledge is very tough.

Fascinating.

In mathematical research it is not uncommon for ideas to be discovered and rediscovered during the passage of time. An idea may "belong to" its original conciever I suppose. My advisor years ago stated he didn't think there were any truly original mathematical ideas anymore. I disagreed.

Sometimes this process leads to embarrassing revelations like having a paper rejected because Newton had your idea first!

Sometimes this process leads to embarrassing revelations like having a paper rejected because Newton had your idea first! — jgill

And even Newton admitted to standing on the shoulders of giants. It seems appropriate to mention Wittgenstein's private language argument, which is not quite an argument, more a demonstration, that language, and therefore conceptual thought, cannot be entirely private and personal but must form a relation to the shared language. Otherwise it could not make any sense, even to its originator.

I think the op's instincts are about correct, and that all ideas are part of a long human conversation, or series of conversations in which ideas develop from the friction of mutual understanding and misunderstanding in such a way that no one can ever claim sole ownership.

Well, to assess something as mine is to be possessive; and possessive is contradictory too benevolence. In other words, Taken, and Given, are the two main ideas given within this context. Give is to lack control in the exchange, to take is to assess control, so I'm going to postulate that when you say "are these thoughts mine?" You mean to incline in a form of possessive behaviour, to assess control over a thought. Likewise, to assess control over a thing, whether it be something or someone else, is indicative of free will, so for the sake of simplifying things (and my argument :P) i'm just going to say that free will exists in this scenario.

Now to take control of something in my belief is to control its aspects, or its properties. With that established, we can now take a look at the scenario. This scenario you proposed:

"do I take credit for my athletic abilities?"

Well, the ability was henceforth "given" to you. That illustrates a lack of control. However, this ability is constrained by a parameter, specifically athleticism. In other words, you need a use to portray your ability. This use is considered possessive, and non reliant on given factors.

This begs the question: If I put my abilities to use, do I control them?

Well, I don't really know. Maybe this helped a little bit though.