Jeffrey Bell on Spinoza’s conatus: 

[A] key function or effect of our appetites is to select against objects, to select against excessive differences and determinations, for these differences and determinate objects may undermine the ratio of motion and rest and hence undermine (kill) the very durational existence of the body itself. God, on the other hand, as absolutely indeterminate and self-caused substance is the infinite enjoyment of existing that affirms all differences. God, however, is absolutely indeterminate substancein actu rather than in potentia and thus God does not have to select against difference. God is the absolute affirmation of difference rather than the limited affirmation of difference that characterizes bodies like us.

This is related to the way that Whitehead’s God, too, affirms all differences, or rather all potentialities (he envisages all eternal objects, indiscriminately).

For Spinoza, as summarized by Bell, our finite, limited appetites “select against difference” and for self-continuation; however, “our ultimate appetite is not… simply to persevere within the fixed proportion of motion and rest that is the formal essence of our body, but rather it is to affirm the absolutely indeterminate condition that does not select against difference, that does not act towards a particular end or goal,” i.e. the ultimate conatus is that of Deus sive Natura, with which we identify in the third kind of knowledge: “a conatus that is endless, that is absolutely indeterminate and not to be confused with any determinate ends or goals.”

For Whitehead, in contrast, there is no third kind of knowledge; individual entities can never identify (I am not sure if this is the accurate word) with God, and the “appetite” of those individual entites is not directed towards self-preservation but towards difference and change (which indeed means, that the entity “perishes,” but thereby leaves behind an inheritance for subsequent entities).