diff --git a/src/ast.rs b/src/ast.rs
index 2514108..23178c6 100644
--- a/src/ast.rs
+++ b/src/ast.rs
@@ -491,6 +491,8 @@ impl Formula
 {
 	pub fn and(arguments: Formulas) -> Self
 	{
+		assert!(!arguments.is_empty());
+
 		Self::And(arguments)
 	}
 
@@ -566,6 +568,8 @@ impl Formula
 
 	pub fn or(arguments: Formulas) -> Self
 	{
+		assert!(!arguments.is_empty());
+
 		Self::Or(arguments)
 	}
 
diff --git a/src/format.rs b/src/format.rs
index b88b8af..15daba8 100644
--- a/src/format.rs
+++ b/src/format.rs
@@ -240,6 +240,8 @@ impl<'formula> std::fmt::Debug for FormulaDisplay<'formula>
 			{
 				let mut separator = "";
 
+				assert!(!arguments.is_empty());
+
 				for argument in arguments
 				{
 					write!(format, "{}{:?}", separator, display_formula(argument, precedence))?;
@@ -251,6 +253,8 @@ impl<'formula> std::fmt::Debug for FormulaDisplay<'formula>
 			{
 				let mut separator = "";
 
+				assert!(!arguments.is_empty());
+
 				for argument in arguments
 				{
 					write!(format, "{}{:?}", separator, display_formula(argument, precedence))?;