From a recent talk I gave:
When a tree falls in the forest, a pressure wave is borne by the air, but there is no sound if there is no ear to detect the vibration and no brain to perceive that vibration as sound. On the airless moon there is no medium to convey a pressure wave. “The Sound of Silence”. Silence is what you hear when a tree falls on the moon.
Our eyes do not see any object directly except by reflection. In a mirror, the eye sees a reflection of a reflection of light from an object where the light comes from someplace else. When you discover a car hurtling towards you, your eye only sees a reflection of light from the car approaching, but the light comes from elsewhere. It is fortunate that the light happens to travel faster than the car coming to mow you down. (I note, in passing, that it would have been a far more intelligent design if our eyes had their own inbuilt light sources – laser beams perhaps – but what we would see would still be reflections.)
Our reality is limited by our senses. We are blind to what our senses cannot detect. We cannot see the ultraviolet light all around and we can not detect infra-sounds surrounding us. There is infinitely more that we can not perceive or even detect. Even my thoughts are limited by my imagination. What I cannot imagine, I cannot think of. Without experience, I cannot understand what hunger means to a starving person. Information from the outside world is first filtered by what our senses can detect. Then, it is interpreted and perceived within the limits of our brains. I cannot convey the pressure wave my ears detect, but I can try to describe the sound I hear. But all that I can communicate is limited by my language. The structure and vocabulary of the languages I know cannot cope with all the nuances of emotion and sounds and sights and smells and tastes of what I perceive I experience.
Where I hear cacophony my son hears music. What I perceive as the worst stench in the world can be perceived as the delicate fragrance of surstromming by a Norrlänning.
There are no facts that are not perceptions and there are no truths that are not interpretations in a brain. To make a judgement is to be biased. Being unbiased is not always right. To discriminate is a consequence of thought. Discrimination is not always wrong. To be different is to be unequal. Inequality is not always undesirable. To reward is a consequence of deserving. Equality is not always wise. The question is whether one is just in ones actions. But what is just depends on where the observer is positioned.
My objectivity is not necessarily yours. I have no objection if others have different opinions to mine, even if theirs are invariably wrong. My point is that objectivity is inevitably, and always, subjective.