Editing Subject and object (philosophy) (section)

=== Substance theory ===
An attribute of an object is called a property if it can be experienced (e.g. its color, size, weight, smell, taste, and location). Objects manifest themselves through their properties. These manifestations seem to change in a regular and unified way, suggesting that something underlies the properties. The change problem asks what that underlying thing is. According to [[substance theory]], the answer is a substance, that which stands for the change.

According to [[substance theory]], because substances are only experienced through their properties a substance itself is never directly experienced. The problem of substance asks on what basis can one conclude the existence of a substance that cannot be seen or scientifically verified. According to [[David Hume]]'s [[bundle theory]], the answer is none; thus an object is merely its properties.