**TL;DR - Nothing is more basic and real than time. Yet, here we are today still debating on whether or not it exists, is real, is an illusion, is relative, or is abstract. What is time really?** Despite all of the varied and plausible theories regarding time, I very strongly believe that time is (only) an abstract concept. However, time is (only) an abstract concept until an event or action has been realized. Once this happens, then it can be perceived as real. The most well-known theory is that of German-born theoretical physicist, Albert Einstein, whose work is known for its influence on the philosophy of science. He developed the theory of relativity which incorporates two interrelated theories, namely, special relativity and general relativity. According to Nola Taylor Redd (2017) who is a contributing writer for Space.com., special relativity applies to all physical phenomena in the absence of gravity. That is to say, that the laws of physics are the same for all non-accelerating observers and the speed of light in a vacuum is independent of the motion of all observers. Whereas, general relativity explains the law of gravitation and its relation to other forces of nature. That is to say, this theory determines that massive objects cause a distortion in space-time, which is felt as gravity. So basically, his theory of relativity as a whole states that the faster we go, the more the time is affected. According to Natalie Wolchover, senior writer and editor for Quanta magazine (2020) Einstein wrote in 1955, weeks before his death, “the distinction between past, present and future is only a stubbornly persistent illusion.” So here we can already see that despite Einstein's theory/theories on time, he also believed that time was an illusion, at least within these three concepts mentioned here. Well, according to Andrew Jaffe who is a cosmologist and head of astrophysics at Imperial College London, Carlo Rovelli, a theoretical physicist believed that time is an illusion. He theorized that reality is just a complex network of events onto which we project sequences of past, present and future. The whole Universe obeys the laws of quantum mechanics and thermodynamics, out of which time emerges. This is why our perception of where time comes from and how it ‘moves’ or changes does not (necessarily) agree with our physical reality. Rovelli further goes on to explain that the apparent existence of time as based on our perceptions and physical descriptions, doesn’t come from knowing (something) but from not knowing (something). That is to say, time and the acquisition of information moves in the ‘forward’ direction. Clearly then, time is a basic yet essential concept as it has been explored by scientists, mathematicians, philosophers, psychologists, etc., as well as, 'ordinary' people in order to make sense of the world around us. It is a concept that was realized from an abstract idea, constructed by multiple metaphors (symbols, images, comparisons, representations)as a consequence of literal everyday experiences. Interestingly enough, while these metaphors are abstract, they are also grounded in our specific experiences. So while these physicists, mathematicians, philosophers, psychologists, etc. have theorized what they believe and perceive time to be – relative, illusion, real, imagined, uniform, etc., we realize that we still do not have a definition that is concrete enough to explain (exactly) what time is. What we do have though is a very varied impression of what time is. That being, that we cannot theorize or assume time as an independent entity, especially since how we relate to time is usually with regard to something else. For example, time and space, time and motion, time and events (or a specific event), etc. Furthermore, time is directional – it flows, irreversible – it has one direction, segments – can be categorized into past, present and future, continuous – infinite, and measurable – able to make (certain) calculations. Therefore, I believe that the concept of time is an abstract one, as we do have an experience of time but that experience is always in comparison with (our) real experiences of events. That is to say, our experience of time is grounded in other experiences. Sources: 1) Why Time Is Relative, Explained in Under 3 Minutes https://www.sciencealert.com/watch-the-famous-twin-paradox-of-special-relativity-explained [accessed January 24, 2021]. 2) The illusion of time https://www.nature.com/articles/d41586-018-04558-7 [accessed January 24, 2021]. 3) Einstein's Theory of General Relativity https://www.space.com/17661-theory-general-relativity.html [accessed January 24, 2021].

I agree that time is an abstract concept. It is a tool created by humans to make sense of a complex world. A way to make the immaterial passage of events into a conceivable, material thing. I reject essentially all theories that rely on universalisms. To disagree with this opinion would be saying that time is a concrete and immutable element of reality that is divorced from human perception. But it isn't. It is a method by which humans make sense of the world, like transmitting thoughts through spoken language. We have taken an idea that we cannot fully understand and concentrated it down to its most important elements. I think this is how we conceptualize time.

Although time as we know it, and by that I mean how humans perceive time in terms of seconds, minutes, hours, days, years etc. is abstract, time in the sense that things constantly move forward is real and concrete. Time *does* exist outside of our consciousness in terms that nothing in the universe is frozen at any particular moment. Fotini Markopoulou-Kalamara, a theoretical physicist at the Perimeter Institute argues that time is not an abstract concept and that it is concretely real: ‘Time seems to be real. Things happen. When I clap my hands, it happened’. [1] Whether we apply that action to the human categorisation of time (which would be how many seconds did it take to clap) or not, the event still did happen and time moved on since that event. Does that not mean that time does exist as a truth, rather than a concept, which can identify that events will always be passing? Therefore time does exist in a clear format that measures events constantly happening, showing that the universe is unable to be static and ‘frozen in time’. It is humans who have made the concept of time abstract by trying to categorise time into different linear amounts which do not truly exist according to physicists. [1] ‘The Illusion of Time: What's Real?’, (https://www.space.com/29859-the-illusion-of-time.html)