Truthness of Invalid Conclusions

hotranchsauce

Hi, I have a question:

Premise: A -m-> B --> C

Invalid Conclusion: A --> C

Is A --> C necessarily false? Or is it just not necessarily true? Or do we simply not know?

LSAT Lizard

It isn't necessarily false- it's just an unknown that could be true, could be false.

In conversation you would probably never saw 'most' when you mean 'all.' But technically, something that is true of 'all' of something is also true of 'most' of those things, also true of 'some' of those things, also true of 'few' of those things, etc. So from A -m-> B, we cannot conclude that A --> B. So A --> C is a possibility.

hotranchsauce

Ok, awesome. Thanks for the reply. I have a follow up question if I may. With the same premises:

Premise: A -m-> B --> C

Can we conclude anything to "must be false" ? I mean besides just a mundane contradiction such as it's not the case that A -m-> C

@"LSAT Lizard" said:
It isn't necessarily false- it's just an unknown that could be true, could be false.

In conversation you would probably never saw 'most' when you mean 'all.' But technically, something that is true of 'all' of something is also true of 'most' of those things, also true of 'some' of those things, also true of 'few' of those things, etc. So from A -m-> B, we cannot conclude that A --> B. So A --> C is a possibility.

LSAT Lizard

I don't think so. The only rule I'm inferring from these premises is A -m-> C, so the only 'must be false' information we have would be limited to mundane/direct contradictions of either that or one of the premises.