Paul of Taranto

Perhaps the best known of his works is his Theorica et practica, which defends alchemical principles by describing the theoretical and practical reasoning behind it.

It has also been argued that Paul is the author of the much more widely known alchemical text Summa perfectionis, generally attributed to the spurious Jabir, or Pseudo-Geber.

For example, a bird could be considered the substance, generally combining characteristics such as feathers, a beak, and the ability to lay eggs.

Sculptures and painters, for example, use nature (marble for statue, paint etc) to create various forms of art.

They take natural materials and manipulate them in such a way (chiseling a statue, combining colors/drawing shapes, patterns, and figures) to create artistic works.

Secondary qualities include white, black, sweet, bitter, hard, soft, sharp, and dull.

Physicians are considered to practice perfective art since they attempt to control the four humors, which by their definition are characterized by the primary qualities.

[5][6][7] An analogous modern example of extrinsic versus intrinsic changes is the difference between a physical and chemical reaction.

When mercury came in contact with metals such as gold, silver, copper, tin, or lead, an amalgam resulted.

[8] Paul addresses one of the many arguments against the sulfur-mercury theory: that intermediate substances cannot exist between the pure elements and the “final product.” Therefore, metals cannot be broken down into sulfur and mercury.

In Theorica et practica, Paul first presents this argument before declining it in a contra and pro fashion.