Try this for thirty seconds. Do not think about a pink elephant. The elephant appeared. You did not choose it.
The Yoga Sutras describe the mind as Chitta — the accumulated repository of all impressions, which generates thoughts in patterns determined by its own structure rather than by the conscious choice of the witnessing awareness. The thoughts arise from the Chitta's processing. The witnessing awareness — Purusha — observes this process but does not generate it.
If thoughts arise from Chitta rather than from deliberate choice, then the identification of the witness with the thoughts — the sense that I am thinking this, this thought is mine — is a confusion of levels. The Purusha is taking ownership of the Chitta's output and calling it its own.
The neuroscience is now confirming what the yogic tradition described structurally. The readiness potential — a measurable brain activity — precedes the conscious awareness of the decision to act by several hundred milliseconds. What presents itself as choice is, at the neural level, the awareness of a process already underway. The sense of voluntary authorship may be less fundamental than it appears.
The practical implication is not nihilism. The actual domain of freedom is in the response to the thought rather than in the production of it. Patanjali's practice addresses precisely this: the cultivation of the gap between the arising of the thought and the reaction to it — the space in which genuine response, rather than automatic reaction, becomes possible.