Keats often puts it better than I can even begin. Some of my favorite bits:
I am certain of nothing but of the holiness of the Heart’s affections and the truth of Imagination – What the imagination seizes as Beauty must be truth – whether it existed before or not – for I have the same idea of all our passions as of love: they are all, in their sublime, creative of essential beauty.
O for a life of sensation rather than of thoughts! It is a ‘Vision in the form of Youth,’ a shadow of reality to come. And this consideration has further convinced me, – for it has come as auxiliary to another favorite speculation of mine, – that we shall enjoy ourselves hereafter by having what we called happiness on earth repeated in a finer tone and so repeated. And yet such a fate can only befall those who delight in sensation, rather than hunger as you do after truth. Adam’s dream will do here, and seems to be a conviction that imagination and its empyreal reflection is the same as human life and its spiritual repetition. But, as I was saying, the simple imaginative mind may have its rewards in the repetition of its own silent working coming continually on the spirit with a fine suddenness – to compare great things with small – have you never by being Surprised with an old Melody – in a delicious place – by a delicious voice, felt over again your very Speculations and Surmises at the time it first operated on your Soul – do you not remember forming to yourself the singer’s face more beautiful than it was possible and yet with the elevation of the Moment you did not think so – even then you were mounted on the Wings of Imagination so high – that the Protrotype must be here after – that delicius face you will see.