Bataille's "heterology" – from the Greek word for difference – concerns the different as such. It is the difference that must be expelled from the same in order for the same to be the same. In bodily terms: excretions of all kinds; in the body-politic: sacrifice and the sacred. For Bataille such expenditure is both a law of nature and the locus of our highest needs. But, if so, we must also acknowledge an inconvenience. Reason would homogenise everything, but what is reason to do when it encounters what it excludes? When it comes into contact with paroxysms of laughter, weeping, screaming, orgasm, or exultant destruction? What can it do when, having admitted the inadmissible, in the ecstatic pursuit of "clear consciousness," these paroxysms surge through reason itself? That is why for Bataille there could not, strictly, be any "science" of such an object. There could only be a "practical heterology."