Objective

Let's start with an objective definition of color:

Colors represent a visible range of frequencies of the electromagnetic spectrum, wherein visible refers to electromagnetic radiation which can get caught by the eye and interpreted by the brain.

Subjective

Upon examination, this definition doesn't exhibit objectivity at all! In particular, let's interrogate “can get caught by the eye and interpreted by the brain.” Other species, from birds to bees, can “see” ultraviolet light, which lies outside the human-visible range. Even within our own species, colorblind and otherwise visually impaired people don't perceive the same range of the electromagnetic spectrum; blind people don't perceive any of that range.

We could adjust our objective definition of color to represent:

1. Any frequency of the electromagnetic spectrum, visible or not

or more narrowly

2. Any frequency of the electromagnetic spectrum, visible to at least one person

However, these come off to me as stuffing a square-shaped peg into a triangular hole. More meaningfully, we can define color as a psychological phenomenon. Under this definition, color becomes subjective: from some perspective, color represents a distinguishable frequency of the electromagnetic spectrum.

Empirical

Defining color subjectively better explains our empirical observations about color. For example, researchers have found both the Tarahumara people and the Himba people have more difficulty than English-speaking people distinguishing blue from green.¹ For these people, blue and green don't represent separate colors as they do for us; their languages don't have separate words for blue and green.²

Conclusion

The subjectivity of something as basic as colors really highlights how subjective our world can become once we investigate it. Understanding that others “see” differently helps us practice perspective-taking.