Parva Naturalia and Ambigua

On Sense and the Sensible.
On Memory and Recollection.
On Sleep and Waking.
On Dreams.
On Divination in Sleep.
On Length and Shortness of Life.
On Life and Death.
On Breathing.
On Youth and Old Age.
On the Motion of Animals.
On the Progression of Animals.
On the Spirit. original: "pneuma"; in ancient Greek biology, this refers to a vital "breath" or substance that carries life-force through the body.
On the Cosmos.
On Virtues and Vices.
On Physiognomics. The study of a person's character or fortune from their outward appearance, especially the face.
On Colors.
On Things Heard.
On Plants.
On Marvelous Things Heard.
On Mechanics.
Problems.
On Indivisible Lines.
On the Situations and Names of Winds.
On Xenophanes, Zeno, and Gorgias. A treatise discussing the philosophies of these earlier Greek thinkers.

On Sense and the Sensible

Since we have already defined the nature of the soul original: "psyche" in itself, and discussed each of its powers individually, our next task is to conduct an investigation into animals and all living things, to determine which activities are unique to them and which are shared. Let what has already been said about the soul be taken as our foundation; let us now speak of the remaining matters, beginning first with those that are primary.

It appears that the most important traits—both those shared by all animals and those unique to some—are common to both the soul and the body. Examples include sensation, memory, passion, desire, and appetite in general, as well as pleasure and pain. Indeed, these are found in almost all animals. In addition to these, some traits are shared by all things that partake in life, while others belong only to certain animals. The most significant of these occur in four pairs:
1. Waking and sleep
2. Youth and old age
3. Inhalation and exhalation
4. Life and death

We must examine what each of these is and for what causes they occur. It is also the duty of the natural philosopher original: "physikos"; a scholar who studies the physical world and laws of nature. to consider the primary principles of health and disease, for neither health nor disease can exist in things deprived of life. Therefore, most researchers of nature end their studies with the principles of medicine, while those physicians who practice their art in a more philosophical manner begin their medical studies from the laws of nature.

It is clear that the aforementioned traits are common to both the soul and the body. All of them either occur alongside sensation or through sensation. Some are "affections" (temporary states) of the soul, some are "habits" (permanent dispositions), others are for protection and preservation, and others result in decay and deprivation. That sensation is produced in the soul through the mediation of the body is evident both through reason and observed facts. However, regarding sensation and the act of perceiving—what it is and why this experience occurs in animals—has already been discussed in our work On the Soul.

An animal, insofar as it is an animal, must necessarily possess sensation; for it is by this that we define what it is to be an "animal." On an individual level, the senses of touch and taste follow all animals by necessity: touch for the reasons mentioned in On the Soul, and taste for the sake of nourishment. Taste distinguishes between what is pleasant and what is painful in food, so that the animal may flee from the one and pursue the other. Broadly speaking, flavor is an experience related to the nutritive part of the soul.

The senses that operate through external media—such as smell, hearing, and sight—belong to those animals capable of movement. In all who possess them, they exist for the sake of preservation, so that they may perceive their food in advance and pursue it, while fleeing from things that are bad or destructive. However, in animals that also possess intelligence original: "noesis", these senses exist for the sake of "the good life." They bring news of many differences in the world, from which the understanding of intellectual concepts arises for both theoretical and practical purposes.

Among these senses, sight is superior for the basic necessities of life, but hearing is superior for the mind, albeit "by accident" original: "kata symbebekos"; Aristotle means hearing isn't inherently smarter than sight, but it is the vehicle for speech, which carries knowledge.. The power of sight reports many diverse differences because all bodies partake in color; thus, we perceive "common sensibles" (such as size, shape, motion, and number) most clearly through sight. Hearing, on the other hand, only reports differences in sound and, for some animals, differences in voice.

Yet, "by accident," hearing contributes the greatest share to wisdom. Speech is the cause of learning because it is something heard. It does this not by its own nature, but by accident, for speech is composed of words, and each word is a symbol. Consequently, among those deprived of either sense from birth, the blind are more intelligent than those who are deaf and mute. We have previously discussed the specific power of each of the senses.