What leads you to say that?
Perhaps there is a way to travel around the world without money or eat chocolate without money or travel while eating chocolate. In my mind there is no doubt it's possible even if I don't know how to right now or I don't know the possible opportunity cost which might be prohibitive (like giving up family to start a career as a chocolate sales representative for Asia). I have faith it's possible and faith I will find a solution if I look into it.
An ISTJ told me something similar regarding his schedule while on vacation. He said I would try to do everything I could think of while he prioritized and did only a fraction of what I "saw" as possible to do.
You see how different the outlook on tasks is? Because of this and because
Si is my Anima (and Ne yours) I ask you to attempt to explain and pinpoint the "knot" in your mind which gives you this knowledge of what is possible, what not and hence what needs to be done. The internal process and the convictions that lead you as an ISTJ.
Is it based on previous experience (as Si descriptions would suggest)?
I am giving you my Ne-Ti POV hoping it might be helpful to establish some common ground for communication so we understand what the other means (on the inside of our heads).
I read somewhere that Ti realizes words are metaphors for internal processes that can't be shown to others and seeks maximum precision in words to maximize the commonalities in the used metaphors. Based on INTP posts I can tell this way of speaking is troublesome to read and hope the topic sparks your interest (my Fe speaking

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Type theory is fun!