We can observe a seed, and call that “reality”. We cannot see, at that moment, the development and growth of the future tree, which represents the “ideal”. When we observe a caterpillar, we cannot see that in a short span of time, it will transform into a butterfly. Reality, which we can see, hear, touch, taste and smell, represents the life of the world around us, and it is easy to acknowledge it as “real”. The developments of the future, however, appear to our minds as insubstantial and as flights of imagination. If we look back, however, through history, we can see innumerable examples of what were considered to be unreal, idealistic, imaginative speculations, that actually represented the future that eventuated. It is therefore essential to recognise that in a similar way, today, those things which we call unrealistic, idealistic, may actually represent a next future development reflected in our deepest aspirations and strivings.
Sri Aurobindo notes: “And that must be why in thought, in art, in conduct, in life we are always divided between two tendencies, one idealistic, the other realistic. The latter very easily seems to us more real, more solidly founded, more in touch with actualities because it relies upon a reality which is patent, sensible and already accomplished; the idealistic easily seems to us something unreal, fantastic, unsubstantial, nebulous, a thing more of thoughts and words than of live actualities, because it is trying to embody a reality not yet accomplished. To a certain extent we are perhaps right; for the ideal, a stranger among the actualities of our physical existence, is in fact a thing unreal until it has either in some way reconciled itself to the imperfections of our outer life or else has found the greater and purer reality for which it is seeking and imposed it on our outer activities; till then it hangs between two worlds and has conquered neither the upper light nor the nether darkness. Submission to the actual by a compromise is easy; discovery of the spiritual truth and the transformation of our actual way of living is difficult: but it is precisely this difficult thing that has to be done, if man is to find and fulfil his true nature. Our idealism is always the most rightly human thing in us, but as a mental idealism it is a thing ineffective. To be effective it has to convert itself into a spiritual realism which shall lay its hands on the higher reality of the spirit and take up for it this lower reality of our sensational, vital and physical nature.”
Sri Aurobindo, The Human Cycle: The Psychology of Social Development, Chapter 22, The Necessity of the Spiritual Transformation, pp. 241-242