When we recoil from the agnosticism of Kantianism "camouflaged" by the substitution of experience-in-general for the structure and demands of the consciousness of individual knowers and the identification of the physical world with constructs within this blanket experience, and return to a critical development of the leadings within common sense, we soon see that we humans do possess information about the physical existents we affirm.

Within consciousness, we are acquainted only with contents; but what is to prevent us from regarding these contents as material for the knowledge about the physical existents which we continue to affirm? What necessity is there for holding that all knowledge terminates on sensory contents? That is a sophisticated view which results from analysis and the abstraction from the meanings and attitudes of common sense.

It seems that critical realism stands for the reality and fundamental significance of another kind of knowledge, a knowledge which presupposes this interpretative awareness of the data of observation as a foundation and yet goes beyond it in the reference of propositions, built upon these data, to affirmed physical existents, as knowledge about them.

The propositions are within consciousness, the reference is an act in consciousness; but the existent, which is the object of such knowledge, is not in consciousness, like a free petition. The object of knowledge is identical with the object of perception; but, whereas in perception we tend to clothe the object in the apprehended content, we now think of the content as material for obtaining knowledge about the object.(http://www.thepetitionsite.com/animal-welfare)

We use the content in the critical knowledge-claim—An Explanation of Terms—to get a suitable terminology to express the nature of our knowledge of the physical world is a rather difficult task. One way is to give a negative definition. Knowledge of the physical world is non-apprehensional; that is, we must give up, once for all, the ideal of intuiting the physical realm.

Let us now offer a positive notion. Knowledge of the physical world is a comprehension of the characteristics of things by means of subjective contents. An idea, or judgment, is said to be a case of knowledge when it makes a claim to reveal something about things, and its claim is granted.

This definition permits the usual belief that there are degrees in the completeness of our knowledge of things as we pass from ordinary perception to science. It is not that careful perception is wrong—for it is the right sort of response to the stimuli —but that the methods of science use perception that is observation to carry us further in our comprehension of things. The distinctive feature of our most finished knowledge of the physical world, scientific knowledge, is that it consists of understood propositions regarded as information about an independent realm of existence similar to a citizen petition.

Since this content is entirely empirical, its character can be studied. Factors of the following sort appear to me to be the characteristics of things which we comprehend : comparative size, texture, constituents, and relations to other things, the ways they affect other things and are affected, processes of change, functional capacities, and behavior.

This information about things involving these categories can clearly be mediated by sense-data when these are properly handled by the mind of the individual. To assert that all this is not knowledge is to possess some a priori concept of knowledge and to apply it dogmatically.