Can you walk and chew gum at the same time?
Can you do - or think - two things at once? I only ask because I am beginning to wonder if it's a rarer feat than I'd realised.
Here is what I have in mind. Last week, I wrote a column in the Guardian about the Goldstone affair, triggered by the semi-retraction that the South African judge had delivered a few days earlier.
The headline was: Where's the Goldstone report into Sri Lanka, Congo, Darfur – or Britain? In the column, I argued that, whatever Goldstone meant or did not mean in his latest comments, his inquiry into the Gaza conflict of 2008-9 had originated in a mentality that regarded Israel as mattering more and behaving worse than any country in the world.
I was referring to the body that commissioned the report in the first place, the UN Human Rights Council. A staggering 32 of the 67 resolutions it passed up to 2010 related to Israel - just under half.
Only one country is under permanent review, on the agenda for every meeting of the UNHRC - Israel. And only one country is blessed by a rapporteur whose mandate never expires - Israel.
In a world that includes the tyrannies of Belarus, North Korea and Saudi Arabia, I argued, this makes no sense at all.
And yet, in its obsessive interest in Israel, the UNHRC - whose predecessor body was once headed, laughably, by Muammar Gaddafi - is true to a vein of thinking that stretches far and wide.
It includes, I went on, those sages who insist that the "core" of the Middle East's woes is the Israel-Palestine conflict, that the number one problem afflicting peoples from Tehran to Tripoli is not the dictatorships oppressing them but Israel.
It also includes those activists who can barely stir themselves to deplore the slaughter in Congo, Darfur or Sri Lanka - the latter killing between 7,000 and 20,000 Tamil civilians, displacing a further 300,000, just as Operation Cast Lead was under way - but who nevertheless become feverishly excited at the first hint of misconduct by Israel.
There was, I noted, no Goldstone report into Sri Lanka's brutality, no Royal Court play deploring the innate wickedness of the Sri Lankan people, no proposal for an academic boycott of Sri Lanka. Only Israel is singled out for that treatment.
The response to that piece was swift, aspects of it unsettling. Some on the right applauded me. At last, I had seen the light: surely this meant I would no longer be a critic of Israeli policy. Some on the left denounced me: surely this was proof that I was now an apologist for Bibi Netanyahu and the occupation. But both sides are wrong. It is perfectly possible to believe that Israel's 44-year rule over conquered land has been a disaster for both Israelis and Palestinians and, simultaneously, to recognise that the Israeli occupation is not the number-one human rights issue in the world and that ending it will not bathe the wider Middle East in sweetness and light.
I can hold both views at the same time.
I can also be vigilant about antisemitism, spotting it in even the most respectable places, and stand firm against, for example, the academic boycott - while simultaneously deploring the alarming slide towards McCarthyism in Israel, typified most recently by the Knesset bill gagging public use of the word "naqba", the term used by Palestinians to describe their view of the events of 1948. I can hold both views at the same time.
Or I can welcome Judge Goldstone's declaration that Israel's own internal investigations "indicate that civilians were not intentionally targeted as a matter of policy" - and, simultaneously, worry that there are many charges in his original report that he has not withdrawn and which remain unanswered.
I can hold both views at the same time. I can walk and chew gum.
Yet all too often we act as if it is one or the other. Either the occupation is wrong - or Israel is singled out unfairly. When, in fact, both statements can be true.
We can both love Israel and believe its current course is dangerously misguided. The challenge is to hold on to both ideas at the same time. Not easy - but essential.