It is possible to know one without the other, however the first experience becomes the baseline upon which other experiences are compared and measured against forming a spectrum.

Take a baby for instance, early in life they are exposed to milk, the feeling of being close to their parents during feeding and the feeling of a full stomach (happiness). However, this becomes the reference point to compare feelings of being alone and hungry (sadness).

If a child experiences nothing but absent parents and malnutrition, the child will not know it is sad because there is no comparative reference point. Its just normal.

Another example, a long time ago when life expectancy was much lower and daily life was very hard, the circumstances needed to feel happiness were much lower. A woman living a hard life in an isolated wilderness suddenly receives a fine dress from a distant city and, compared to her daily harsh reality, it brings her extreme happiness.

Compare that to modern times where daily life is much easier and we have access to almost anything we want. Not surprisingly, people find it harder to find happiness. Why? Because they don’t have the comparative negative baseline.