1 What is it like to be colour-blind? A Case Study in Experimental Philosophy of Experience Mind & Language: https://doi.org/10.1111/mila.12370 Please refer to the published version. Keith Allen, Philip Quinlan, James Andow, and Eugen Fischer What is the experience of someone who is ‘colour-blind’ like? This paper presents the results of a study that uses qualitative research methods to better understand the lived experience of colour blindness. Participants were asked to describe their experiences of a variety of coloured stimuli, both with and without EnChroma glasses—glasses which, the manufacturers claim, enhance the experience of people with common forms of colour blindness. More generally, the paper provides a case study in the nascent field of experimental philosophy of experience (Ex-XPhi). 1. Introduction 1.1 What is it like to be colour-blind? Colour blindness, or ‘Colour Vision Deficiency’ (CVD), affects around 8% of the male population and around 0.5% of the female population in European populations. CVD perceivers vary depending on which types of colour experiences are affected and why. The most common form of colour deficiency, and the focus of this paper, is standardly called ‘red/green’ colour blindness. This itself comes in two varieties depending on which of the retinal receptor types (L, M, or S) are lacking: in protans it is L cones, in deutans it is M cones. Perceivers who are red/green colour-blind also differ in the ‘dimensionality’ of their vision. Dichromats (protanopes and deutanopes) only have two functioning retinal receptor types, and as such can match any given coloured light with a mixture of two others. Like ‘normal’ trichromatic perceivers, anomalous trichromats (deuteranomalous