Writing twenty four years later, Nagel's position (1998) remains essentially similar. In a nuanced, concluding passage, Nagel is very careful to distinguish between causation and entailment. He posits the need for an entirely novel, “third conception”:
even though no transparent and direct explanatory connection is possible between the physiological and the phenomenological, but only an empirically established extensional correlation, we may hope and ought to try as part of a scientific theory of mind to form a third conception that does directly entail both the mental and the physical, and through which their actual necessary connection with one another can therefore become transparent to us.
For Nagel a new theory-driven “solution to the mind-body problem” remains “unimaginable,” but he has moved to state that “it may not be impossible.”
Nagel, Thomas (1974)What Is it Like to Be a Bat? Philosophical Review, 83: 4, October 1974, pp. 435-50.
Nagel, Thomas (1998) Conceiving the Impossible and the Mind-Body Problem. Royal Institute of Philosophy annual lecture, London: February 18, 1998. Published in Philosophy73: 285, July 1998, pp. 337-352.