All instincts are desires, and all instincts are therefore feelings. The feelings we have, being things, can be known by us, or not known. Our knowing also can be known or not known.
Life begins with desire; in fact, one way, it is self as desire. When a baby is born, there is the instinct to live (which is always. the general, basic instinct); this means in the baby there is a feeling, seen as cause, that is, desire, to keep on living, to live; and this feeling is not known by the baby. The baby at 24 can say: "I desire to live"; at which time, the instinct, being affirmed, is more than that; but also, still that.
The instinct to live, with a recently born infant, in so far as it is a desire not known, is like the instinct to twiddle one's thumbs when the twiddling comes from a desire not known. Instincts can be seen as magnificent and trivial; but in each instance, they are instincts.
© 1945 by Eli Siegel