Love: Risk, Inevitability, Certainty and Infinity

I went on a run this morning and I was doing so was pondering the documentary I watched on Queen on BBC4 last night.  Husband and I had a chat about it as I am embarking on some risky health behaviour, which chimes with what Freddie Mercury was up to in the 1980s.  We know one thing and that is at some point we are going to die.  But how certain are we of that?  Isn't inevitability only a hindsight thing?  And then when you think about certainty, a 50/50 risk seems quite good and I know my risky behaviour is less than that - otherwise the doctors would stop me doing it full stop.  It is a 'calculated risk'.  But did Freddie do the calculations I wondered as I was running round the field?  And I thought about the sun rising in the morning, again a very high (has got to be hasn't it?) probability.  Will I ever know if infinity exists?  Are there scientists out there who believe in certainty?  Because if we say that something is 100% going to happen then surely we are believing in infinity, which is an ideal thus busting the material view out of touch.  Perhaps I am so uncertain because dementia, like life, risk, certainty, infinity and inevitability is just too complex a thing to say anything concrete about.