“pi exists” … it’s a ratio…but what do we mean by ratio? unless we are true-believer platonists, we don’t believe numbers or ratios exist. numbers and ratios are processes. they are ACTS, entailing an observer. hence it is clearer to use verbs and gerunds to talk about them. natural numbers are counting. decimals are multiple interations of counting with decimal places used for accounting purposes.
pi as an “infinite” decimal expansion is, i’ll go ahead and use the word, INCONCEIVABLE. you cannot see it in your mind, or sense it in your mind in any way. but pi to a certain number of decimal places is conceivable.
yet, you say, we can picture a circle and its diameter, the implication being that we can picture the ratio of the circumfrence of the circle to its diameter. actually, we cannot picture it as a static frame, but we can animate it into an internal movie…a process. it is the ACT of imagining the diameter pushed up against the circle once, twice, three times in a continuous line, and then having a little left over. for the partial decimal expansion, you cut the diameter into ten equal pieces, then a hundred equal piece, then a thousand…and attach one of the first pieces onto the continuous line, four of the second piece, one of the third…3,14159…continuing this process until you get bored.
pi is a process, an act by an observer…hence it doesn’t exist - any more than farting exists. it is not sitting there, inherent in the circle itself; it only “exists” as a possible action we can take.