Examine the PDF chart attachment (D2-Level of proof – DEFINITIONS AND SCALE).
See also pages 72 74 in Ferdico 11th Edition.
Substantive law defines what constitutes a crime (murder, rape, robbery). Whether or not a crime has been committed is defined by substantive law. (See page 4 Ferdico 11th)
Below is a link to Chapter 19 of the Texas Penal Code covering the types of criminal homicides in Texas. This provides an example of substantive law.
Select the Penal Code, and then Chapter 19 in the drop down menu.
Procedural law is the standard operating procedure for criminal justice professionals (police, prosecutors, and even jurors). Whether or not a police officer has probable cause to arrest a person for murder is a matter of procedural law.
Below is a link to chapter 14 of the Texas Code of Criminal Procedure. This provides an example of procedural rules for Texas police officers regarding when arrests may be made.
Select the Code of Criminal Procedure, and then Chapter 14 in the drop down menu.
It is easy to explain the penal code definition of murder (a substantive law) to a jury so that they may determine if the defendant is guilty of the offense. It is much more difficult for a jury to determine the meaning of proof beyond a reasonable doubt (a procedural concept) the level of proof necessary to convict a person of a criminal offense.