IF-Then with a qualifier?

as5324therapy

What's up with people that use If-then statement with a qualifier like "could". If X, then Y must follow. It's necessary. What's the point/impact of "could" follow. It annoys me that the necessary condition has an escape. Example:

If not enough new homes are built in 2016, then home prices could rise.

LSATisland

Yes, the frustration of applying the LSAT to the world and expecting nice, clear categories. People just mean "likely" or "probably", and are avoiding categorical statement because things are typically not that clear and categorical.

nye8870

Swell example @as5324therapy of the vague logic in the real world. I see this as: "If demand for housing increases, then there is a possibility home prices will rise." Contrapositive: ?

nye8870

Contrapositive: "If there is no possibility of home prices rising, then there is no demand for homes."....?

hlsat180

Causal vs. Conditional Reasoning

Q.E.D

There are different ways to schematize that, just depends on which features are relevant to the context. Looks like it's probably confusing because the consequent could be interpreted as a proposition in a modal context, i.e. P->◇Q.

The conditional you've learned is called the material conditional. It's the easiest formal construct for natural language conditionals, but it's distorted owing to its limited expressive power. Richer systems like modal logic are better equipped to capture the niceties of ordinary language.

In brief, that's perfectly fine logic. I think your problem is just that sentence logic (SL, aka Lawgic) isn't equipped to schematize all the reasoning in ordinary language and, for that matter, the LSAT.

For more on problems with the material conditional, see
https://en.m.wikipedia.org/wiki/Paradoxes_of_material_implication

And
http://plato.stanford.edu/entries/logic-modal-origins/