After Aristotle wrote on substance, a theory developed about the attributes that could inhere in a substance. They were distinguished between primary and secondary.

For example, colour is a secondary characteristic because when I boil a purple cabbage the colour leaks away, but the mass of the cabbage remains. It is primary. Or, when I view it through a blue glass, the colour changes but the mass again remains the same.

But could there be in some other possible (or impossible?) world a mass-glass through which if one looks at a cathedral or a purple cabbage, its mass changes but not its colour? That is, are primary attributes primary in this world, but possibly secondary in another?

  • 1
    What theories of physics or chemistry are you entertaining for this question? We understand that the change in colour of cabbage is due to chemical changes in the cabbage; and that the apparent change of colour when looking through a coloured glass is because of light absorbtion by the glass. Meanwhile, mass changes depending on reference frames in Einsteinian relativity (assuming one speaks of 'relativistic mass' rather than 'the mass-equivalence of kinetic energy', a distinction without a difference). What variations of natural laws do you accept in this question? Jul 2, 2013 at 10:03
  • @deBeaudrap: as far as Liebnizs logically possible worlds. Could one suppose that gravitational waves are visible? The main problem I see is that two people looking at a purple cabbage through a red and green glass respectively will see different colours; but how would that translate into mass-glasses? What would it mean for two persons to see a cathedral with two different masses? Jul 2, 2013 at 10:58
  • Do you expect that logical contradictions might arise, from supposing that mass could vary based on some change of mode of perception, and colour not? How would discovering the answer not amount to trying to construct a different model of physics, from the Higgs Boson (to give a comensurable meaning to "mass") and electromagnetism (to give a comensurable meaning to "colour") on up? Jul 2, 2013 at 11:01
  • @MoziburUllah: You seem to be making some bold assumptions here. It is not the colour of the cabbage what leaks away, but small cabbage particles that colour the water. Similarly, it is not correct to claim that the mass of the cabbage remains constant; a lot of chemical processes occur during cooking, and the weight of the cabbage does change, implying a change in mass. Do you have a clear definition of primary vs. secondary attributes?
    – CesarGon
    Jul 6, 2013 at 16:38

3 Answers 3


Possible worlds rely on, and are defined in terms of, logical possibility. If given the current physics of our universe, primary qualities cause secondary qualities, there is no logical contradiction - no self-contradiction - in the description of a different universe ('possible world') in which the reverse is the case and secondary qualities cause primary and in this sense are primary.

In our world, (this is awfully simplified) eyes respond to light waves that bounce off objects with mass and position (primary qualities) and translate them into nerve signals which travel to the brain where they are interpreted as sensations of colour (secondary qualities). A different world is logically possible in which we first have a sensation of colour, and this causes nerve signals which travel from the brain and in turn cause light waves the occurrence of which creates objects with mass and position.

Such a state of affairs could reasonably be described as one in which (to repeat) secondary qualities in our world cause primary and in this sense are primary in a logically possible world.

Under the physical laws of our actual world this is total fantasy. But it is logically possible in that its description involves no self-contradiction.

It is nothing to the point that any or all of this is conceptually incoherent given the physical laws of our actual world. As a logical construction a possible world is not subject to any constraints imposed by the physical laws of our actual world.


That world exists, it's ours.

Firstly, I haven't found any definition of primary and secondary attributes. I'll suppose that a secondary attribute can vary while the object doesn't and primary attributes do modify the object.

But I see some misconceptions, in Special Relativity heating the cabbage will increase its mass (if you suppose that there is not loss of atoms).

The other problem is that when you see an object through a glass, you're modifying how you see its color. So it should be compared to measuring the object's weight while you are pushing the scale, its mass (color) remains the same but not what you measure (see).

It's mostly a matter of semantics. Why do you say it's a cabbage, since it's chemical composition has changed?

If you try to find some primary attributes I think that they should be in elementary particles. But if String Theory is correct, then they would just depend on the string's frecuency.

So I think it's quite difficult to distinguish between primary and secondary attributes (at least with the examples you gave).


This depends to a great extent on what you think to be necessary. If you think that our physical laws are necessary true, then the answer is 'no, there are no possible worlds that behave that way'. If you think that our physical laws are only contingently true if true at all, there may be a possible world that behaves differently, and at which our secondary attributes become primary.

Since you asked for impossible worlds aswell, and if impossible worlds are such that they include squared circles, and horses that are no horses... Then surely, there is an impossible world at which the secondary attributes of our world become primary.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .