Discussion of Knowledge of Heat in "The Assayer" by Galileo

In the Assayer, Galileo begins his argument by stating Mr. Sarsi is incorrect for thinking, modern philosophy must follow the beliefs of other philosopher or ‘’ the reasoning of someone else’’(Galileo,59). He believes acquiring mathematical knowledge is necessary to understand philosophy. Galileo then proceeded by explaining his stand on motion and cause heat. He begins by pointing out people's common mistake in their knowledge of heat.

People think heat is a ‘’genuine accident or quality’’, but it is not. He stated Corporeal substance is necessary: the object is bounded, has shape, is related to other bodies, occupies time and space, it’s in rest or motion, touched or does not touch another body. The primary qualities are different from the secondary properties or our senses. The primary qualities exist regardless of the presence of living things, however, the existence of living beings is fundamental for the survival of secondary properties because the secondary properties only exist in bodies. He presented tickling as an example,’’ this affection belongs wholly to us, and not a whit of it belongs to the hand’’(Galileo,60-61).

Tickling is not a quality inherited by the hand doing it, because a piece of paper or feather can cause the sensation the hand cause. Galileo believed our senses ‘’ have no greater an existence’’ he continued explaining how senses are related to elements. Touch is a motion, and when a body comes into contact with a person, it then produces a sensation known as touch. Sense is material than others and arises from the solidity of matter, which is related to Earth. Some bodies are endlessly dissolving into litter particles, and some fall feather, while others rias. Water base particles evaporate, which cause the tongue to encounter taste. Fire-related particles produce an odor when heated to rias in the air and reach the nose.Vibration in the air creates sounds. External bodies use size, shape, number, and motion to present secondary properties in humans, and without as they wouldn't exist.

Galileo did not clarify the relationship between vision and light because it’s complicated and he doesn’t have enough understanding also to explain what he knows would take a long time, so he didn’t get into vision. Galileo then returns to his argument that heat is the causation of motion. He affirmed heat is created by tiny corpuscles in a particular shape and moving at a certain speed, they penetrate our bodies and pass through us the affection is heat. The penetration can be pleasant or unpleasant depending on ''the number and speed of the particles as they prick and penetrate it’’(Galileo,63). It is suitable ''if it is beneficial to our insensible vital functions'', moreover unpleasant when it causes too much of a ''separation and dissolution of our substance''. Galileo stated when the fire move in penetrates direction our bodies will then experience the feeling of heat. If there were no ‘’animate and sentient’’ to contact the heat, it would not exist. When two things rubbed together, the friction generates motion, Which allows a particle to be released and cause a fire by moving through bodies parties. To sum up, heat is secondary peculiarities which only exist because of our bodies ability to interpret fire as they pass through our bodies.