Conway Says, "If Spirit and Body Are So Contrary One

Conway says, "if spirit and body are so contrary one to another, so that a spirit is only life, or a living and sensible substance, but a body a certain mass merely dead; a spirit penetrable and indiscerpible [having no separate parts], but a body impenetrable and discerpible [having separate parts], which are all contrary attributes." Conway then asks the following question: What is that which joins or unites them together?