Brian Cox in his book "Why does E=MC2?" talks about "useful science" and its opposite. He politely says that people are entitled to make conjectures on any subject under the sun, but for their work to be considered scientific it must make "useful" predictions. Useful, of course, in the sense that the work predicts (d) when (a) (b) and (c) first happen.
I'm not too sure that sociology or economics or geography deserve to be termed science, which isn't to denigrate them any more than I'd denigrate the arts. On the other hand, thermodynamics and aerodynamics are clearly 'useful' in both senses of the word.
So far so black-and-white. But what of vulcanology? Is it a science or just a way of describing... after the event? Does it deserve the 'ology' or should it be relegated to an 'ography'? As for this book, does it contain numbers and equations? Does it make falsifiable predictions? (Yeah, I hear you say, 'flippin' well buy it and you'll find out!')
Even the layman can make predictions in the field of vulcanology, but here is my question: Is the signal to noise ratio higher amongst vulcanological professionals than amongst non-specialists?
To return to Brian Cox, I dunno if he has actually accomplished anything as a scientist; when he stands before some natural wonder, looks into the camera and says, "Wow, that's really amazing!" he's a mere entertainer.
To state that something can only be considered science if it can make useful predictions and to consider only the mathematical aspects of physics such as aerodynamics to be the only sciences is to be like Lord Kelvin who asserted that "There is nothing new to be discovered in physics now, All that remains is more and more precise measurement". Some sciences such as vulcanology and astrophysics contain too many unknowns for prediction in the light of our present knowledge. These are new sciences (plate tectonics has only been accepted for 50 years) and presently we are in the stage of acquiring knowledge after the event and prediction is in its fledgling stage. This is at the stage that physics was in the time of Bohr or Maxwell, but physics was still a science even then. If only the precision of thermodynamics is accepted as a science, and it should be noted that Lord Kelvin used this to prove beyond doubt that the Earth was less than a million years old, then are quantum physics and chemistry sciences? Both of these are governed by the uncertainty principle and the vagaries of statistics. We know that in the Cretaceous the GMST was much higher than today, and we know there was much more vulcanism both at mid-ocean ridges and subduction zones. At times of lower temperature vulcanism was less. This book tries to provide reasons for this in a readable form, but at the moment there are a lot of theories around the subject. That does not make it less a science.