Is there an objective reality independent of the mind?

One of the most prominent philosophical discussions between the 18th and 20th century was that between realism and idealism. 

On the one hand, idealism, which has its beginnings in Plato and was further developed later by Berkeley, Kant, Schopenhauer, and Hegel, postulated that it is impossible to discuss objective reality separate from the mind. As the name suggests, idealism claims that the only knowable thing is the idea of a reality created by the mind rather than an objective reality in itself. In simpler terms, the focus is on the inability to distinguish reality from appearance. Once Kant firmly established idealism on the philosophical map, he asserted that he had made a Copernican revolution in philosophy insofar as he switched the classical view of the relationship between the object and the subject by placing the latter in the center. Until then, the overarching view was that there is a real external object which the subject can perceive, but the existence of the object is independent of that perception. Conversely, Kant argued that the subject (i.e., the mind) can't gather knowledge on objects as they are, but rather merely on the mental images which the objects imprinted on the mind. This being so as all knowledge happens through the mind which means that once the subject starts to perceive or reflect on an object, he is necessarily doing it by firstly creating an idea of the object in the mind. In some sense, it is impossible for the mind to escape itself as the escaping necessarily precludes the mind. The mind can, thus, be seen as somewhat of a projector that shapes the reality around it. Now, the question is what exactly is in front of the projector? From what and on what does it project the images? For this, Kant made one of the crucial moves in his philosophy; namely, the divide between the thing-in-itself (the noumenon), which exists independently of the mind, and the representation of the thing (the phenomenon) or how the thing appears in the mind (the mental image of the thing). The only thing that is knowable to the mind is the phenomenon. In other words, the world we sense around us is merely the representation of the “real” world.  Moreover, the way in which the mind comprehends the phenomenon is by its innate tools which he referred to as categories. It is in this regard that Kant also (at least as he thought) finalized the debate between empiricists and rationalists; he placed himself in the middle by stating that knowledge is, indeed, built through experience, as empiricists argued, but the mind is not a passive receiver of experience, but actively participates in creating the external experience (so it must have some sort of an innate knowledge, which is a rationalist claim). Likewise, time and space are a priori tools with which the mind builds its ideas of reality. It is impossible to perceive an object without it being in a certain place and at a certain time. The aforementioned categories include that of cause and effect, quantity, plurality, etc. – all of the ideas that we must have prior to experience to allow the experience to happen by structuring it in meaningful and understandable parts. Plato’s theory of forms suggested something similar as it was trying to unwrap the classic philosophical problem of universals; namely, what is it that enables the mind to perceive certain objects as being a part of the same set? What is it in a chair that makes us perceive it as a chair – i.e., why do we see a small wooden tripod belonging to the same group (of chairs) as a large golden throne? There is scarcely anything similar in them apart from the fact that they are used for sitting. To answer this, Plato argued that all individual objects that the mind perceives are merely a manifestation of a single universal idea/form which enables the mind to make connections between the particular instances of the object (i.e., to make the connection between all different individual chairs and see them as chairs). In other words, this universal idea gives all single chairs their “chairness” (their essence). Furthermore, Plato maintained that the world of universal ideas is, in fact, the real world. The world in which people live deals only with particular instances of the idea – it is like they are living in a cave perceiving only the shadows of the real objects while thinking that the shadows are indeed real. The connection between Plato and Kant is obvious in this regard; what Plato sees as the objects/ideas of a different world, Kant calls the noumenon or the thing-in-itself. Finally, it is important to note that idealism is more like a group of outlooks rather than a single one as there are many different variations of it. What associates them is that the idea of an object precedes the object itself.

On the other hand, realism goes hand in hand with the classic scientific view of the world; there is an objective reality which one can perceive, investigate and reflect on, but those actions do not “create” the reality. In other words, an object exists independently of the subject. If a tree falls in the forest, it has fallen regardless of there being a conscious agent present, as the famous philosophical anecdote goes. The existence of the tree is completely separate from the perception of it. For this view, less explanation may be provided as it is in line with common sense. People largely interpret the world in such a way, while idealism is mostly reserved for a subset of philosophers or those individuals with an unusual interest in epistemology. Furthermore, apart from common sense, the scientific method can be seen as the supporting evidence of realism; contrary to idealism which is gathered solely by theoretical thinking, realists have an empiric/practical backing to their claims. Not to go into too much detail on this topic as it is complex, Karl Popper differentiated science from pseudoscience with the method of falsification. It is a method through which one doesn’t look for supportive evidence for his/her claim, but rather tries to disprove/falsify the theory with all that is in his/her power. Consequently, the theory that underwent the largest number of falsifications, but kept standing is the correct one (so far). Moreover, the theories which cannot be falsified, to begin with, aren’t considered scientific at all. An example of this is astrology in opposition to astronomy; the former makes claims which don’t leave room to be disproven such as “your current emotions are caused by the current planet organization” – one cannot do anything with this claim factually. You can either accept it or not, but it will be based solely on emotion as there is no way for anyone to prove or even test whether the sentence is correct or incorrect. On the other hand, true science, like astronomy, makes predictions in its theories which can then be tested and proven to be false. From this, idealism would go into the category of pseudoscience. One cannot find any evidence that will disprove Kant’s claim that the object doesn’t exist without the mind. Whatever you say, he can say that it is your mind that is talking, and therefore, you are again talking merely about the ideas of the mind. What is more, Popper often criticized idealism by stating that there is a large discrepancy between the amount of discussion on it and the practical use we get from those discussions. It is solely a theoretical debate in which one can take either side, but will not receive any new useful information on the world apart from theorizing about the nature of human knowledge. There are numerous accounts of comical situations in the history of philosophy while discussing this topic; once, an opponent of idealism threw a rock at one subjective idealist while saying that he thus refutes his theory. Whether you are an idealist or not (i.e., whether you believe the rock is real or not), the rock will hurt you all the same. Finally, Bertrand Russell provides an important argument in favor of realism by stating that idealism limits the possibility of human knowledge. Seeing that knowledge is formed by the mind, to know means to have an idea in the mind. Consequently, that idea must form in relation to something external from the mind. Otherwise, once the mind gains knowledge, it is receiving it solely from itself which is not possible - the mind cannot learn something new from itself because then it isn’t something new, but was rather present in the mind beforehand. From this paradox, it can be concluded that in a way, idealism attacks the possibility of knowledge itself.

In summary, the debate between realism and idealism is one of the larger ones in the history of philosophy. Idealism brought many interesting ideas (some of which are yet to be disproved) while having some of the most influential philosophers on their side. Furthermore, its insistence on putting the mind in the center is difficult to argue against given that arguing itself comes from the mind - which further proves its point. On the other hand, it is questionable whether its claims truly bring something worthwhile to the table in the practical sense. The discussion itself is important and both sides furthered the understanding of human knowledge, but it just may be that there are other somewhat more practical problems to be addressed in philosophy. In any case, given the historical and philosophical importance of this debate, along with a myriad of quality arguments on both sides, it will certainly be discussed in time to come.