Sensation (n.) grasps a direction, not an object: it says which way the cold or the bright lies, not what is causing it.
Sensation (n.) is already action: it makes the creature coincide with the middle of a gradient, and tropism can occur in stillness as well as in movement.
Sensation (n.) does not hold the object: before anything has a fixed identity, a living being is already oriented, and orientation is what comes first.
Sensation (n.) is contact between the matter we are and the matter outside us: touching and feeling are acts of atoms, and a soul is made of them too.
Sensation (n.) is transduction rather than synthesis: a gradient is grasped from its center, which unfolds into hotter on one side and colder on the other.
Sensation (n.) is not raw material waiting for the mind to stamp a form on it; that picture is just hylomorphism smuggled into the theory of knowledge.
Sensation (n.) is not a window onto substances but a relation between a living being and its surroundings; it seems fragile only because we ask it to do what it never could.
Sensation (n.) is not a raw fog handed to the mind to be shaped; it is the senses' play of differences, and perception is its twin, the integration that makes the differences cohere.