“We can only feel contrasts; we know only differences, and we need them in order to see.”Georg Christoph Lichtenberg · Caietele de însemnări · 1799 · Caietul K, însemnarea 29
We don't perceive things, only the differences between them: without contrast, even the most constant thing becomes invisible.
The senses are built to detect change, not constant states. You stop hearing a clock ticking after a few minutes in the room, and you feel your skin's temperature only when you touch something else. Sight works the same way: uniform light becomes invisible. Lichtenberg draws an epistemological conclusion from this: knowledge is relative, and we always need a term of comparison before we can see anything at all.
If we feel only differences, then habit is not laziness but the way our senses work. When a bad situation stays unchanged, it vanishes from perception, like the smell of a kitchen you stand in every day. You did not get used to it by choice; there is simply nothing left to compare it with. This has a practical consequence: to judge a life, a job or a relationship honestly, you need a real contrast, not willpower. A week elsewhere reveals more than a month of reflection in the same place. But if everything is relative, an awkward question appears: is there any objective measure of things at all, or only chains of comparison?
Why it matters Useful when you want to understand why you have grown used to a bad situation, or why happiness is only noticed when it follows a hard stretch.