WikiMechanics

David Hume, 1711—1776.

Do you think that electrons are objects? Have you ever seen a proton? What is an object anyway? Well, according to the ontological theory of bundles developed in the 18th century by Scottish philosopher David Hume an object consists of its sensory properties, and nothing more. This agrees with the first meaning given for object in a popular Canadian dictionary as "anything that is or may be apprehended by the senses; especially a tangible or visible thing".¹ But according to substance theory an object is more than just its sensory properties. This point of view becomes relevant in discussions about free will, liberty, the value of human life and other important concerns.

For WikiMechanics let us take Hume's position, at least as a definition for physical objects, but with the constraint that we should be cautious in consideration of human bodies. This is partly to defer bundle versus substance disputes, but also because our reference sensations are based on the human body and we want to avoid getting into illogical circular reasoning. This proviso limits the range of validity of WikiMechanics. Accordingly we define a physical object as anything that may be perceived by the senses, especially a tangible or visible thing. Discrete physical objects are often called particles.

The foregoing definition applies to all the sensations we have used to describe events. So every event, large or small, can also be thought of as a particle. But it may get confusing to change back and forth between describing events versus identifying particles. So we tend to use the word event and symbol $\sf{P}_{ \it{k}}$ for specific sensations like coldness or redness. On a larger scale we prefer the word particle and symbol $\sf{P}$. And in between, for quarks, we may use either mode of description, depending on context.

Summary

Noun		Definition
Object	$\sf{\text{Anything that may be perceived by the senses.}}$	3-2