Here again someone will say, but just because I know John really wrote the book of John doesn't mean that John wasn't lying. That's where McDowell --- and the other books --- will talk about logic and human nature. Most of the disciples were martyred, terribly. Who would die for something they knew to be a lie?
John may have really believed / perceived what he wrote and simultaneously been wrong about it. Human perception is unreliable, malleable over time, and subject to distortion from a wide range of internal bias and external stimuli. Plenty of people around the world genuinely believe in religious and spiritual experiences that directly contradict the experiences that you hold to be true.
I said the same thing myself, having witnessed a number of miracles in my Pentecostal world. Once I lost my faith I was shocked to realize that nothing I'd witnessed was conclusive. Far from it, in fact. Having had a lot of 'backstage' access as the son of the pastor, more than one miracle turned out to have not been a miracle at all.
John may have really believed / perceived what he wrote and simultaneously been wrong about it. Human perception is unreliable, malleable over time, and subject to distortion from a wide range of internal bias and external stimuli. Plenty of people around the world genuinely believe in religious and spiritual experiences that directly contradict the experiences that you hold to be true.