We discuss the conversation between Bryan Magee and Anthony Quinton on Spinoza and Leibnitz at https://www.bbc.co.uk/programmes/m002l4zh?seriesId=unsliced.  We started from Descartes’ proposition that mind and body are distinct substances and the problem of then explaining their interaction.  Spinoza noted that if God is infinite, he must encompass both, and indeed all things are different aspects of one single substance that presents as both mind and matter.  God is the cause (in the sense of the four causes of Aristotle) of everything.  Spinoza's values seem to chime well with those of environmental ethics we are studying in Philosophy Group 2.  Leibnitz started from the other end of the scale, holding that every single thing has an associated notion and this is connected to every other notion, so it knows its relationship to everything around it.  Possible metaphors are users of the internet and maybe DNA.  From this he can propose that it is possible to think our way through these relationships and get to any knowledge without experiment.  He did admit that it is easier to observe, sy, the temperature of a distant star than to do the analysis.  His theory leads to a deterministic universe and thus no free will, but Leibnitz argues that God has determined that this is the best of all possible worlds - a view lampooned by Voltaire in “Candide”.