Primary and Secondary Qualities

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Every student of philosophy knows how to draw up the lists of primary and secondary qualities: on the left go extension, size, shape or figure, solidity, motion or rest, and number; on the right go color, sound, scent, taste, heat and cold. But what is the principle of the distinction? Does it have to do with objective versus subjective? Categorical versus dispositional? Intrinsic versus extrinsic? Or several or none of these?

To summarize this section, the basis of the primary/secondary quality distinction for Reid cannot be that primary qualities reside in objects and secondary qualities do not (as Berkeley’s Hylas has it), since both sets of qualities reside in objects. Nor can it be that primary qualities resemble their associated ideas or sensations and secondary qualities do not (as Locke has it), since in neither case is there any resemblance. So what, if anything, is the basis for the distinction?

– James Van Cleve, Problems from Reid

54 thoughts on “Primary and Secondary Qualities”

  1. Reciprocating Bill: Very common in the US northeast and midwest through the 1940s or so (my home was constructed in 1918, originally with a coal boiler that is STILL THERE (but disconnected). The big disadvantage is that there is no easy way to air condition the structure.

    Almost no moving parts (no fans, pumps etc.) The only moving part in my heating system is the automatic vent damper (keeps heat from escaping up the chimney when the boiler is not firing.)

    Generates “fat heat,” which rises and falls slowly as the radiators condense the steam. This in contrast with the abrupt on-off of scorched air systems.

    Had a look via google and I see domestic steam systems are indeed simple, the distribution taken care of simply by condensation. Interesting that the Hartford loop was invented by an insurance company. It’s the safety aspect that would worry me. BLEVES sound scary. Plus there must be lime-scale to deal with unless replenishing water is already soft or softened.

    Also no chance of making a condensing furnace/boiler work with steam. Recovering the latent heat from water vapour produced by combustion can save 30% on consumption of heating gas or oil.

  2. walto: A lot of people are converting to gas in these parts. But the conversion is so expensive that it takes quite a while for it to pay.

    There doesn’t seem much choice on condensing boilers in the US. They’re compulsory here as a new installation.

  3. Alan Fox: Interesting that the Hartford loop was invented by an insurance company. It’s the safety aspect that would worry me. BLEVES sound scary. Plus there must be lime-scale to deal with unless replenishing water is already soft or softened.

    Boiler explosions due to boiler and return line leaks were distressingly common prior to the invention of the Hartford Loop. The loop prevents the boiler from draining if a leak occurs. The big old coal boiler next to my contemporary gas boiler didn’t have one.

    The key to safety is maintenance – you’ve got fuel, electricity, combustion and water all playing roles in the system. So there are several controls that can shut down the system in response to a problem – the pressuretrol, the low water cutoff (which typically operates an automatic water feed), sensors that detect flame rollout, etc. Plus a pop valve if all else fails and pressure climbs. It all needs to be periodically checked. (I’m due.)

  4. keiths: This thread brings back memories of the astonishing array of noises that steam radiators can make.

    That’s exactly what we’re looking for here at TSZ!

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