The problem is one of opposition between subjective and objective points of view. There is a tendency to seek an objective account of everything before admitting its reality. But often what appears to a more subjective point of view cannot be accounted for in this way. So either the objective conception of the world is incomplete, or the subjective involves illusions that should be rejected.
Thomas NagelEveryone is entitled to commit murder in the imagination once in a while, not to mention lesser infractions.
Thomas NagelMaterialism is incomplete even as a theory of the physical world, since the physical world includes conscious organisms among its most striking occupants.
Thomas NagelIf we tried to rely entirely on reason, and pressed it hard, our lives and beliefs would collapse - a form of madness that may actually occur if the inertial force of taking the world and life for granted is somehow lost. If we lose our grip on that, reason will not give it back to us.
Thomas NagelEverything, living or not, is constituted from elements having a nature that is both physical and nonphysical - that is, capable of combining into mental wholes. So this reductive account can also be described as a form of panpsychism: all the elements of the physical world are also mental.
Thomas Nagel