If man made global warming is really happening, then the polar ice caps will be melting.
The polar ice caps are melting,
Therefore man made global warming is really happening.
Quick question on this one. Why is it a false conclusion?
Is the reason that "the polar ice caps are melting" and "the polar ice caps will be melting" is not the same thing?
I would have answered: Wrong premises but correct conclusion. :confused:
The conclusion may be true (it just depends on whether or not man-made global warming really IS happening, now that probably is true, but still arguable).
The premises also, are probably true. So, let's say that this argument consists of true premises and a true conclusion. It is still an invalid argument.
When evaluating an argument, we first need to see if it logically follows; the actual truth of the premises and conclusion does not matter in this regard, because the form of the argument is either valid or invalid, regardless of the truth value of the statements. With a valid deductive argument, if the premises are true, then the conclusion is necessarily true.
The premises here do not necessarily lead to the conclusion. With this argument, the premises and conclusion could all be true (to our knowledge), but the actual argument does not logically follow, and so it is invalid.
We can represent this in the following manner (had to adjust a couple words for the tense, but the meaning remains the same):
P: Man made global warming is really happening
Q: The polar ice caps are melting
This type of argument is called "affirming the consequent", and is a formal fallacy that is always invalid for a deductive argument.
You could come up with other varieties of this argument, in english, to see clearly how it is invalid, such as:
If I am looking into a mirror, I see my reflection.
I see my reflection.
Thus, I am looking into a mirror.
Now, all of these things could in fact be true at once, but we all know that simply seeing our reflection does not necessarily mean we are looking into a mirror; we could be staring out at a pond, looking into a glass, etc.