I imagine you’re using language like “logically possible” to cloak your statements in an appearance of calm, reasoned discourse, but it doesn’t really mean what you intend it to mean. If the definition of a trans person is someone who feels that their biological configuration is not in alignment with whom they feel themselves to be and someone expresses feeling this way, there is no logical issue here. This person could be lying to themselves or you, but it should be obvious that even if this is the case for some number of people, the possibility that millions of people who report feeling this way are all wrong is vanishingly small. There is no logical problem with the statement, “I feel a certain way.” A statement that is not logically “possible” is something like “It is raining; therefore if I go outside I will not get wet.” You’re free to believe that everyone who claims to be trans is lying or deluded or whatever, but you might as well start doubting when people say they feel tired or sick or happy. We can only take people’s word for how they feel. And if you look into what a lot of trans people go through, and you suspend your personal feelings, you might find you have some sympathy for them.