Under Reality, Boldface indicates basic objects, italics indicates apparent objects.
Under Knowledge, Boldface indicates best known objects, italics indicates objects of opinion
| Reality | Knowledge | |
|---|---|---|
| What | Atoms, material things | Atoms, material things |
| How | Material things are combinations of atoms | Atoms by reason, explaining material things known by senses |
| Reality | Knowledge | |
|---|---|---|
| What | Forms, material things | Forms, material things |
| How | Forms exist separately as patterns of material things | Forms by reason, directly; opinions about material things based on sense experience |
| Reality | Knowledge | |
|---|---|---|
| What | Substances, other material things | Substances, other material things |
| How | Substances are combinations of form and matter | The senses provide all initial information; reason (1) infers what is not available to the senses, (2) grasps the universal element |
| Reality | Knowledge | |
|---|---|---|
| What | God, other thinking things, extended things | God, my mind, mathematics, mathematical properties of extended things, sensible properties of extended things |
| How | God is an infinite thinking thing; I and other minds are finite thinking things; physical objects are extended and unthinking. All finite things are created by God. | The understanding has clear and distinct perceptions of essences. The senses are a fairly reliable guide to what to pursue and what to avoid. |
| Reality | Knowledge | |
|---|---|---|
| What | Bodies | The properties of bodies and the causes of their change |
| How | Bodies are extended in space and exist independently of thought. Thinking is computation, which is motion. | Sense perception exhibits regularities which are generalized to principles of motion. |
| Reality | Knowledge | |
|---|---|---|
| What | Substance, modes of the attributes of substance | Substance, what follows from substance, contingencies |
| How | Substance has infinitely many infinite attributes, including thought and extension. Individual minds and bodies are modes of thought and extension, respectively. | From common notions and adequate ideas of the properties of things, and by intuition. |
| Reality | Knowledge | |
|---|---|---|
| What | God, essences, created substances, bodies | That God exists and has created the best possible world. Eternal truths of logic and mathematics. Laws of physics. Existence and properties of created substances. |
| How | Essences or possibilities exist in the mind of God. The best combination of these is created by God. A substance's essence contains all its properties. | The principle of non-contradiction establishes possibilities. The principle of sufficient reason establishes which possibilities exist. |