In this short note, a brief response is presented against the arguments presented by the famous philosopher George Berkeley (1685-1753) against skepticism. Berkeley presented three arguments against skepticism- Uniformity of sense experience, Relativity argument and the Master argument and by this three arguments he tried to prove that primary and secondary qualities of objects are mind dependent and thus sensible things are mind dependent. Hence, all material objects are mind dependent.

Berkeley’s argument against skepticism (via Philonous) states that sensible things can only exist in the mind and so they are mind dependent. Thus there is no material substance in the world. This argument opposes the view that we immediately perceive mind independent objects. In his argument against skepticism there are three arguments: uniformity of sense experience, relativity argument and master argument. His basic argument is that because matter is only known to us by its sensible qualities, it is impossible to describe or even imagine matter without these qualities. For in the absence of sensible qualities matter, by definition, loses its essential qualities. Furthermore, sensible qualities are not inherent in matter. Rather, they are ascribed and understood by the mind. Color, sound, temperature and even shape are relative qualities entirely dependent on a mind. Hence all sensible things are mind dependent.

We can sufficiently prove that not all sensible things are mind dependent if we can find a single sensible thing that can exist without a mind. In this regard, we can thought of a thought experiment as follows: let there be a simple voice recognition software which can recognize certain words. Now we cannot say that the software understands the sound of the words but we can clearly say that the software recognize the ‘existence’ of certain sound of words. From here we can say that the existence of the sound of those words are recognized by a software. Now there are a few things that we can say: (1) the software has a mind and hence the sound of the word is not mind independent (2) the software does not have a mind.

If we take the first assumption we have to redefine the definition of mind so that a certain voice recognition software can have a mind. But one thing must be noticed that these kinds of software are just some physical logic based machine program. In other words they are nothing more than an inert object controlled by some pre-defined commands. If we attempt to define so that something like this is a mind or has a mind then our conception of mind gets way too much out of common sense. So much so that anything that can be driven by giving command such as machines, sensors, traffic lights have a certain mind. Obviously we cannot count on this kinds of assumption as it takes us far away from the common perception of the definition of mind.

If we take the second assumption that the software doesn’t have a mind then it seems that the sensible quality is detected by a mindless physical object. Therefore, sensible qualities can exist without any mind and so it proves the ‘existence’ of mind independent sensible objects. One can argue that the sound of the words are a product of mind itself but the source of the sensible object is irrelevant in this context. Although it seems like a strong reasoning against the claim of Berkeley, an equally good response can be given to counter this. According the Berkeley’s theory, objects are just a bunch of properties and all the sensible properties are mind dependent. So when different objects interact with each other what really happen is that the sensible properties of the objects interact with each other. This can be illustrated by a simple example- let us take one bucket of red colored water and a bucket of green colored water. Clearly the red water have a sensible property of color red and green water have a sensible property of color green. Now when we mix the two water we can see orange colored water emerges which has a new sensible property of color orange. Likewise, all object interaction are nothing but interaction of the sensible properties which may create new sensible properties. Now if we look at the example of the voice recognition software, it can be seen as an interaction of some sensible properties of objects. It is obvious that the sound has a sensible property. Also the voice recognition software is connected to a sensor to capture the sound which, being an object, also has some sensible properties. These sensible properties interact with each other and just like the previous example a new sensible quality emerges which makes us believe that the voice recognition software detects the ‘existence’ of the sound.

Although the above response quite strongly gives good reasoning in favor of Berkeley’s argument, new problem emerges if we simply modify our thought experiment. Let’s now assume that the sensor which captures the sound is a remote radio sensor that is connected to the software via radio wave. So the sensible property of sound is now carried via the radio wave to the voice recognition software and the software recognizes the sound but radio wave itself has no sensible quality. Now the problem occurs if we analyze the case of radio wave. There is no way to deny the existence of radio wave as it carries a form of sensible quality from one place into another but it itself has no sensible quality like size, shape or color so that one can identify where it is or what it looks like. This example of radio wave proves that there exists some objects which do not have any sensible properties and so they can be identified but they can be used to create interactions among many sensible properties of objects. These kinds of object, as they do not have any sensible quality, are mind independent objects with physical properties. These physical properties are mind independent. So, if these kinds of objects interacts with another object with their physical properties which are mind independent, we can safely say that the other object also has physical properties which can not be mind dependent. So, in the thought experiment, as radio waves interacts with sensors, the properties of the sensors are mind independent. By the same logic, as the sensors interacts with the sound, sound has at least one mind independent quality. This, however, doesn’t necessarily prove that the sensible quality of sound is mind independent. Now, if we consider the fact that the sensible property of the sound is carried by the radio wave and recognized by the software, we can say that the sensible property of the sound is carried by a non-sensible property of radio wave which is not mind dependent. So, if we add this one with the previous conclusion we can say that the sensible quality of the sound is not mind dependent. Hence by this we can conclude that all sensible things are not mind dependent.

In the above discussion, we have actually conducted two important thought experiments (one is a modified version of another). One of them is about capturing sensible quality in a software. From which we can conclude that the software can have minds or we can also say that all the physical interactions are nothing more than the interactions of sensible qualities of objects. The second conclusion is more logical and preferable than the first one but it also introduce us to the next thought experiment. In the second thought experiment, we have the example of radio wave which doesn’t have any direct sensible quality so that we can perceive its existence. This example compels us to admit the existence of non-sensible real objects which interact with sensible objects and thus the sensible objects can not be mind dependent. One can say that the existence of these kinds of non-sensible object is known to us via our senses so there must be some features of the object which are sensible indirectly, if not directly. But the fact is that their existence is known to us not via some their sensible features but via their interaction with other sensible objects. In reality, no one has ever seen the radio waves but it is widely used to carry information and many other sensible qualities and this is the only way we can know about their existence. These kinds of non-sensible objects which interact with other sensible objects poses a great problem for the Berkeley’s theory which claims that there is no material substance in the reality and all the sensible qualities are mind dependent. This also act as a good response to the master argument of Berkeley.