One of the most important criticisms in the philosophy of ecology debates is the criticism directed towards anthropocentricism and rationalism. There are different kinds of rationalist approaches. But we can say that the rationalist approach that is subject to criticism, when we think from the point of view of ecological debates, is the one that grounds anthropocentricism in modern thought. While evaluating these criticisms, it is important for us to bear in mind the differences and resemblances between various rational approaches. In some of these criticism, we find some tendencies such as ontological negation of reason or modern human (being) as the condition of an ecological existence. Criticisms towards anthropocentrism and rationalism in ecological debates have legitimate aspects but how kind of rationalism is supported by modern thought has to be understood. The aim of this paper is to try to differentiate between rationalism which has ecological essence and the one that has not it. Because, if the philosophical underpinnings concerning the construction of the way of ecological existence are to be investigated, it will be seen that it's one of the sine qua non dimensions will be the reason (eco-reason) again.