What is Mathematics? The question is as old as Philosophy itself. Is it a cognitive model, or reality itself? Despite thousands of years of discussion, we still do not know. Not that we have no idea, but we have many partial answers. Can we then stop asking the question? As long as we teach Mathematics, we cannot. What we think about a subject, admittedly or not, influences how we present it, how we teach it. For instance, latent Platonism led to a reader-unfriendly style of mathematical writing that removes any traces of failures or dead ends in the thinking process, only presenting the eternal truth. Therefore, adjusting our philosophical perspective may improve education.

What is computation? What do programmers really do? As if we had not enough trouble with the nature of Mathematics already, the rise of computers further complicated the picture. Computing devices appear to be mathematical engines at a low level, and they can look very different on higher levels. What is a computer then? Since we aim to teach programming to more and more people, the stakes are again high due to the educational considerations.

We invite thinkers who are tackling these issues from different perspectives and with a varied set of methods to contribute this Special Issue. Mathematics and computing keep changing; therefore, it is worth revisiting the fundamental questions.