 Individual natural entities (whether sentient or not, living or not), Andrew Brennan (1984, 2014) argues, are not designed by anyone to fulfill any purpose and therefore lack “intrinsic function” (i.e., the function of a thing that constitutes part of its essence or identity conditions). This, he proposes, is a reason for thinking that individual natural entities should not be treated as mere instruments, and thus a reason for assigning them intrinsic value. Furthermore, he argues that the same moral point applies to the case of natural ecosystems, to the extent that they lack intrinsic function. In the light of Brennan’s proposal, Eric Katz (1991 and 1997) argues that all natural entities, whether individuals or wholes, have intrinsic value in virtue of their ontological independence from human purpose, activity, and interest, and maintains the deontological principle that nature as a whole is an “autonomous subject” which deserves moral respect and must not be treated as a mere means to human ends. Carrying the project of attributing intrinsic value to nature to its ultimate form, Robert Elliot (1997) argues that naturalness itself is a property in virtue of possessing which all natural things, events, and states of affairs, attain intrinsic value. Furthermore, Elliot argues that even a consequentialist, who in principle allows the possibility of trading off intrinsic value from naturalness for intrinsic value from other sources, could no longer justify such kind of trade-off in reality. This is because the reduction of intrinsic value due to the depletion of naturalness on earth, according to him, has reached such a level that any further reduction of it could not be compensated by any amount of intrinsic value generated in other ways, no matter how great it is.