Lockdown arrived in a fidget of activity. I spent the day before helping in my daughters’ school, hoping to feel of use. The teachers were busy photocopying worksheets, trying to figure out what would be required of them in the coming days and weeks. I talked philosophy with the children, class after class, in the large and draughty hall. We talked about aliens who wore sofas on their heads and whether sitting on your sister turned her into a chair. The space fizzed with laughter and chatter. The next day we all withdrew into our homes. Descartes’s Meditations on First…