Two cents (for further discussion see Strawson on Free Will: What are the most persuasive challenges to his position?)

"A person can do what he wills, but cannot choose what he wills" is an a priori argument that rests on two assumptions:

1. That a choice of what to will is not among choices of what to do. That is, will is a priori restricted in levels.
2. If the above statement is true, that one cannot access another level to will, because it leads to infinite regress.

Both claims can easily be contested:

1. There is absolutely no a priori reason (unless assumed to be so, thus a priori denying will) that what to will is not among what to do. That is there is no a priori reason for will to be intially restricted in levels.
2. Even if will is restrcited in levels, there is still no infinite regress in practice, since one, in practice, will have to go only some finite levels deep or up in order to reach the appropriate level to will at that level.

On the Freedom of the Will - Wikipedia

Two cents.

Arthur Schopenhauer, On the Freedom of the Will - Wikipedia

Translation of "On the Freedom of the Will" by Arthur Schopenhauer

For counter-arguments to Schopenhauer's thesis see:

1. What are some counterarguments to Schopenhauer's refutation of free will?
2. Strawson on Free Will: What are the most persuasive challenges to his position?

Schopenhauer began by analyzing the basic concepts of freedom and self-consciousness. He asserted that there are three types of freedom; physical, intellectual, and moral (the terms were sometimes used in philosophy, as he shows in chapter four).

• Physical freedom is the absence of physical obstacles to actions. This negative approach can also be expressed positively: only he is free who acts according to one's will and nothing else. (This is commonly thought to constitute freedom of the will.) But when this simple meaning is used in connection with the will itself and the answer "will is free" is assumed—like with the question "can you will what you willed to will?" (and so on, because then one can always ask for the source of "willing to will" and whether it was free)—one eventually commits an error of infinite regress, because one always seeks an earlier will which the current one adheres to. Also the verb "can", when understood physically in the above question, does not really solve the problem satisfactorily, so other meanings were sought.
• Intellectual freedom results when the mind has a clear knowledge of the abstract or concrete motives to action. This occurs when the mind is not affected by, for example, extreme passion or mind-altering substances.
• Moral freedom is the absence of any necessity in person's actions. As "necessary" means "that what follows from a given sufficient basis"—whereas, likewise, all sufficient bases act with necessity (because they are sufficient), and thus there is no possibility that a cause does not bring its effect—a will containing a free element (liberum arbitrium) and thus arising without necessity would imply the existence of something that has no cause whatsoever and is completely arbitrary and unaffected (liberum arbitrium indifferentiae, freedom of will not influenced by anything). This would be the undetermined part (whereas apart from that something could, possibly, still influence man).
• Self-consciousness is a person's awareness of their own willing, including emotions and passions.

In the course of the analysis Schopenhauer declares that the opposition of necessary is known as contingent or incidental, which is normally encountered in the real world as just relative contingency (a coincidence) of two events—of which both still have their causes and are necessary with regard to them. Two things are incidental, or contingent, to each other when one does not cause the other. He then derives the concept of absolute contingency by extending the former term so that no sufficient basis exists whatsoever; such thing would not be incidental with regard to something, but with regard to all and everything. He concludes that liberum arbitrium indifferentiae would mean exactly such incident (a chance), an absolutely fortuitous or random occurrence. He notes that with such liberum arbitrium indifferentiae one would be equally capable of doing one thing or the other.

According to Schopenhauer, when a person inspects their self-consciousness, they find the feeling "I can do whatever I will as long as I am not hindered." But, Schopenhauer claimed that this is merely physical freedom. He asserted "You can do what you will, but in any given moment of your life you can will only one definite thing and absolutely nothing other than that one thing." Therefore, the Royal Society's question has been answered "No."

On the Freedom of the Will - Wikipedia