Androids vs Vampires

Both androids and vampires tend to be really strong, and to take a lot of 
killing to be rid of. They both can have endless *** without worrying
about 
birth control. But illustrating the fact that sci-fi really is harder to 
write than fantasy, androids are harder to write about than vampires, it 
appears to me.

These reflections were occasioned by the fact that I'm quite enjoying Joel

Shepherd's Sandy Kresnov series, into which he seems to have put a lot of 
thought. But...that deadly but. Did he think about the laws of 
thermodynamics or the facts of biology carefully enough to make me happy? 
Alas, no. Sandy appears to be able to expend energy at enormous rates 
without eating a lot or even breathing hard. Eh? And why does an inorganic

construct thrive so well on ordinary food anyway, even leaving aside the 
energy and oxidation question. She's not even a carbon-based lifeform! And

what's with the idea that she is susceptible to viral and bacterial 
infection with the same suite of agents ordinary humans are? Sorry, Joel,
I 
just don't buy it.

Now a vampire can get along on a few milliliters of blood every few days 
and fail to make an appearance in mirrors despite seeming to be made of 
normal matter, and it doesn't worry me at all. The rules for vampires are 
fantasy rules; all we ask for is consistency.

Fantasy-the last refuge of the hard science fiction fan.