diff --git a/vm/alien.cpp b/vm/alien.cpp
index 84e40a4613..2287263442 100755
--- a/vm/alien.cpp
+++ b/vm/alien.cpp
@@ -12,8 +12,8 @@ char *factor_vm::pinned_alien_offset(cell obj)
 	case ALIEN_TYPE:
 		{
 			alien *ptr = untag<alien>(obj);
-			if(ptr->expired != F)
-				general_error(ERROR_EXPIRED,obj,F,NULL);
+			if(to_boolean(ptr->expired))
+				general_error(ERROR_EXPIRED,obj,false_object,NULL);
 			return pinned_alien_offset(ptr->base) + ptr->displacement;
 		}
 	case F_TYPE:
@@ -40,7 +40,7 @@ cell factor_vm::allot_alien(cell delegate_, cell displacement)
 		new_alien->base = delegate.value();
 
 	new_alien->displacement = displacement;
-	new_alien->expired = F;
+	new_alien->expired = false_object;
 
 	return new_alien.value();
 }
@@ -51,8 +51,8 @@ void factor_vm::primitive_displaced_alien()
 	cell alien = dpop();
 	cell displacement = to_cell(dpop());
 
-	if(alien == F && displacement == 0)
-		dpush(F);
+	if(!to_boolean(alien) && displacement == 0)
+		dpush(false_object);
 	else
 	{
 		switch(tagged<object>(alien).type())
@@ -130,17 +130,17 @@ void factor_vm::primitive_dlsym()
 
 	symbol_char *sym = name->data<symbol_char>();
 
-	if(library.value() == F)
-		box_alien(ffi_dlsym(NULL,sym));
-	else
+	if(to_boolean(library.value()))
 	{
 		dll *d = untag_check<dll>(library.value());
 
 		if(d->dll == NULL)
-			dpush(F);
+			dpush(false_object);
 		else
 			box_alien(ffi_dlsym(d,sym));
 	}
+	else
+		box_alien(ffi_dlsym(NULL,sym));
 }
 
 /* close a native library handle */
@@ -154,10 +154,10 @@ void factor_vm::primitive_dlclose()
 void factor_vm::primitive_dll_validp()
 {
 	cell library = dpop();
-	if(library == F)
-		dpush(T);
+	if(to_boolean(library))
+		dpush(tag_boolean(untag_check<dll>(library)->dll != NULL));
 	else
-		dpush(untag_check<dll>(library)->dll == NULL ? F : T);
+		dpush(true_object);
 }
 
 /* gets the address of an object representing a C pointer */
@@ -170,8 +170,8 @@ char *factor_vm::alien_offset(cell obj)
 	case ALIEN_TYPE:
 		{
 			alien *ptr = untag<alien>(obj);
-			if(ptr->expired != F)
-				general_error(ERROR_EXPIRED,obj,F,NULL);
+			if(to_boolean(ptr->expired))
+				general_error(ERROR_EXPIRED,obj,false_object,NULL);
 			return alien_offset(ptr->base) + ptr->displacement;
 		}
 	case F_TYPE:
@@ -202,9 +202,9 @@ VM_C_API char *unbox_alien(factor_vm *myvm)
 void factor_vm::box_alien(void *ptr)
 {
 	if(ptr == NULL)
-		dpush(F);
+		dpush(false_object);
 	else
-		dpush(allot_alien(F,(cell)ptr));
+		dpush(allot_alien(false_object,(cell)ptr));
 }
 
 VM_C_API void box_alien(void *ptr, factor_vm *myvm)
diff --git a/vm/arrays.hpp b/vm/arrays.hpp
index accf8b3b04..d4cbcc11c3 100755
--- a/vm/arrays.hpp
+++ b/vm/arrays.hpp
@@ -26,7 +26,8 @@ struct growable_array {
 	cell count;
 	gc_root<array> elements;
 
-	explicit growable_array(factor_vm *myvm, cell capacity = 10) : count(0), elements(myvm->allot_array(capacity,F),myvm) {}
+	explicit growable_array(factor_vm *myvm, cell capacity = 10) :
+		count(0), elements(myvm->allot_array(capacity,false_object),myvm) {}
 
 	void add(cell elt);
 	void append(array *elts);
diff --git a/vm/booleans.cpp b/vm/booleans.cpp
index f1f0230c13..538f4b7dce 100644
--- a/vm/booleans.cpp
+++ b/vm/booleans.cpp
@@ -5,7 +5,7 @@ namespace factor
 
 void factor_vm::box_boolean(bool value)
 {
-	dpush(value ? T : F);
+	dpush(tag_boolean(value));
 }
 
 VM_C_API void box_boolean(bool value, factor_vm *myvm)
@@ -13,11 +13,6 @@ VM_C_API void box_boolean(bool value, factor_vm *myvm)
 	return myvm->box_boolean(value);
 }
 
-bool factor_vm::to_boolean(cell value)
-{
-	return value != F;
-}
-
 VM_C_API bool to_boolean(cell value, factor_vm *myvm)
 {
 	return myvm->to_boolean(value);
diff --git a/vm/booleans.hpp b/vm/booleans.hpp
index 498c3f74be..375c8e3756 100644
--- a/vm/booleans.hpp
+++ b/vm/booleans.hpp
@@ -6,7 +6,12 @@ VM_C_API bool to_boolean(cell value, factor_vm *vm);
 
 inline cell factor_vm::tag_boolean(cell untagged)
 {
-	return (untagged ? T : F);
+	return (untagged ? true_object : false_object);
+}
+
+inline bool factor_vm::to_boolean(cell value)
+{
+	return value != false_object;
 }
 
 }
diff --git a/vm/callstack.cpp b/vm/callstack.cpp
index 0b7663e513..838274cff8 100755
--- a/vm/callstack.cpp
+++ b/vm/callstack.cpp
@@ -100,22 +100,22 @@ cell factor_vm::frame_scan(stack_frame *frame)
 	case QUOTATION_TYPE:
 		{
 			cell quot = frame_executing(frame);
-			if(quot == F)
-				return F;
-			else
+			if(to_boolean(quot))
 			{
 				char *return_addr = (char *)FRAME_RETURN_ADDRESS(frame,this);
 				char *quot_xt = (char *)(frame_code(frame) + 1);
 
 				return tag_fixnum(quot_code_offset_to_scan(
 					quot,(cell)(return_addr - quot_xt)));
-			}
+			}    
+			else
+				return false_object;
 		}
 	case WORD_TYPE:
-		return F;
+		return false_object;
 	default:
 		critical_error("Bad frame type",frame_type(frame));
-		return F;
+		return false_object;
 	}
 }
 
diff --git a/vm/code_block.cpp b/vm/code_block.cpp
index 0afd98dd0f..80862bc426 100755
--- a/vm/code_block.cpp
+++ b/vm/code_block.cpp
@@ -66,7 +66,7 @@ void *factor_vm::object_xt(cell obj)
 
 void *factor_vm::xt_pic(word *w, cell tagged_quot)
 {
-	if(tagged_quot == F || max_pic_size == 0)
+	if(!to_boolean(tagged_quot) || max_pic_size == 0)
 		return w->xt;
 	else
 	{
@@ -92,7 +92,7 @@ void *factor_vm::word_xt_pic_tail(word *w)
 image load */
 void factor_vm::undefined_symbol()
 {
-	general_error(ERROR_UNDEFINED_SYMBOL,F,F,NULL);
+	general_error(ERROR_UNDEFINED_SYMBOL,false_object,false_object,NULL);
 }
 
 void undefined_symbol()
@@ -106,7 +106,7 @@ void *factor_vm::get_rel_symbol(array *literals, cell index)
 	cell symbol = array_nth(literals,index);
 	cell library = array_nth(literals,index + 1);
 
-	dll *d = (library == F ? NULL : untag<dll>(library));
+	dll *d = (to_boolean(library) ? untag<dll>(library) : NULL);
 
 	if(d != NULL && !d->dll)
 		return (void *)factor::undefined_symbol;
@@ -147,8 +147,8 @@ void *factor_vm::get_rel_symbol(array *literals, cell index)
 
 cell factor_vm::compute_relocation(relocation_entry rel, cell index, code_block *compiled)
 {
-	array *literals = (compiled->literals == F
-		? NULL : untag<array>(compiled->literals));
+	array *literals = (to_boolean(compiled->literals)
+		? untag<array>(compiled->literals) : NULL);
 	cell offset = relocation_offset_of(rel) + (cell)compiled->xt();
 
 #define ARG array_nth(literals,index)
@@ -196,7 +196,7 @@ cell factor_vm::compute_relocation(relocation_entry rel, cell index, code_block
 
 template<typename Iterator> void factor_vm::iterate_relocations(code_block *compiled, Iterator &iter)
 {
-	if(compiled->relocation != F)
+	if(to_boolean(compiled->relocation))
 	{
 		byte_array *relocation = untag<byte_array>(compiled->relocation);
 
@@ -308,9 +308,9 @@ void factor_vm::update_literal_references(code_block *compiled)
 void factor_vm::relocate_code_block_step(relocation_entry rel, cell index, code_block *compiled)
 {
 #ifdef FACTOR_DEBUG
-	if(compiled->literals != F)
+	if(to_boolean(compiled->literals))
 		tagged<array>(compiled->literals).untag_check(this);
-	if(compiled->relocation != F)
+	if(to_boolean(compiled->relocation))
 		tagged<byte_array>(compiled->relocation).untag_check(this);
 #endif
 
@@ -484,12 +484,12 @@ code_block *factor_vm::add_code_block(cell type, cell code_, cell labels_, cell
 
 	/* slight space optimization */
 	if(relocation.type() == BYTE_ARRAY_TYPE && array_capacity(relocation.untagged()) == 0)
-		compiled->relocation = F;
+		compiled->relocation = false_object;
 	else
 		compiled->relocation = relocation.value();
 
 	if(literals.type() == ARRAY_TYPE && array_capacity(literals.untagged()) == 0)
-		compiled->literals = F;
+		compiled->literals = false_object;
 	else
 		compiled->literals = literals.value();
 
@@ -497,7 +497,7 @@ code_block *factor_vm::add_code_block(cell type, cell code_, cell labels_, cell
 	memcpy(compiled + 1,code.untagged() + 1,code_length);
 
 	/* fixup labels */
-	if(labels.value() != F)
+	if(to_boolean(labels.value()))
 		fixup_labels(labels.as<array>().untagged(),compiled);
 
 	/* next time we do a minor GC, we have to scan the code heap for
diff --git a/vm/code_heap.cpp b/vm/code_heap.cpp
index b7307dd7e6..8caee005fb 100755
--- a/vm/code_heap.cpp
+++ b/vm/code_heap.cpp
@@ -51,8 +51,8 @@ void factor_vm::jit_compile_word(cell word_, cell def_, bool relocate)
 
 	word->code = def->code;
 
-	if(word->pic_def != F) jit_compile(word->pic_def,relocate);
-	if(word->pic_tail_def != F) jit_compile(word->pic_tail_def,relocate);
+	if(to_boolean(word->pic_def)) jit_compile(word->pic_def,relocate);
+	if(to_boolean(word->pic_tail_def)) jit_compile(word->pic_tail_def,relocate);
 }
 
 struct word_updater {
@@ -164,7 +164,7 @@ void factor_vm::forward_object_xts()
 
 	cell obj;
 
-	while((obj = next_object()) != F)
+	while(to_boolean(obj = next_object()))
 	{
 		switch(tagged<object>(obj).type())
 		{
@@ -251,7 +251,7 @@ struct stack_trace_stripper {
 
 	void operator()(code_block *compiled)
 	{
-		compiled->owner = F;
+		compiled->owner = false_object;
 	}
 };
 
diff --git a/vm/collector.hpp b/vm/collector.hpp
index 8156fd1693..69488e04ab 100644
--- a/vm/collector.hpp
+++ b/vm/collector.hpp
@@ -119,7 +119,7 @@ template<typename TargetGeneration, typename Policy> struct collector {
 	the user environment and extra roots registered by local_roots.hpp */
 	void trace_roots()
 	{
-		trace_handle(&myvm->T);
+		trace_handle(&myvm->true_object);
 		trace_handle(&myvm->bignum_zero);
 		trace_handle(&myvm->bignum_pos_one);
 		trace_handle(&myvm->bignum_neg_one);
diff --git a/vm/contexts.cpp b/vm/contexts.cpp
index bed044250e..c914271c89 100644
--- a/vm/contexts.cpp
+++ b/vm/contexts.cpp
@@ -143,13 +143,13 @@ bool factor_vm::stack_to_array(cell bottom, cell top)
 void factor_vm::primitive_datastack()
 {
 	if(!stack_to_array(ds_bot,ds))
-		general_error(ERROR_DS_UNDERFLOW,F,F,NULL);
+		general_error(ERROR_DS_UNDERFLOW,false_object,false_object,NULL);
 }
 
 void factor_vm::primitive_retainstack()
 {
 	if(!stack_to_array(rs_bot,rs))
-		general_error(ERROR_RS_UNDERFLOW,F,F,NULL);
+		general_error(ERROR_RS_UNDERFLOW,false_object,false_object,NULL);
 }
 
 /* returns pointer to top of stack */
@@ -180,7 +180,7 @@ void factor_vm::primitive_check_datastack()
 	fixnum saved_height = array_capacity(saved_datastack);
 	fixnum current_height = (ds - ds_bot + sizeof(cell)) / sizeof(cell);
 	if(current_height - height != saved_height)
-		dpush(F);
+		dpush(false_object);
 	else
 	{
 		fixnum i;
@@ -188,11 +188,11 @@ void factor_vm::primitive_check_datastack()
 		{
 			if(((cell *)ds_bot)[i] != array_nth(saved_datastack,i))
 			{
-				dpush(F);
+				dpush(false_object);
 				return;
 			}
 		}
-		dpush(T);
+		dpush(true_object);
 	}
 }
 
diff --git a/vm/data_heap.cpp b/vm/data_heap.cpp
index 6b09953314..335938acab 100755
--- a/vm/data_heap.cpp
+++ b/vm/data_heap.cpp
@@ -240,10 +240,10 @@ void factor_vm::primitive_begin_scan()
 cell factor_vm::next_object()
 {
 	if(!gc_off)
-		general_error(ERROR_HEAP_SCAN,F,F,NULL);
+		general_error(ERROR_HEAP_SCAN,false_object,false_object,NULL);
 
 	if(heap_scan_ptr >= data->tenured->here)
-		return F;
+		return false_object;
 
 	object *obj = (object *)heap_scan_ptr;
 	heap_scan_ptr += untagged_object_size(obj);
@@ -266,7 +266,7 @@ template<typename Iterator> void factor_vm::each_object(Iterator &iterator)
 {
 	begin_scan();
 	cell obj;
-	while((obj = next_object()) != F)
+	while(to_boolean(obj = next_object()))
 		iterator(tagged<object>(obj));
 	end_scan();
 }
diff --git a/vm/debug.cpp b/vm/debug.cpp
index da8c603254..8fad13d663 100755
--- a/vm/debug.cpp
+++ b/vm/debug.cpp
@@ -236,7 +236,7 @@ void factor_vm::dump_objects(cell type)
 	begin_scan();
 
 	cell obj;
-	while((obj = next_object()) != F)
+	while(to_boolean(obj = next_object()))
 	{
 		if(type == TYPE_COUNT || tagged<object>(obj).type_p(type))
 		{
@@ -275,7 +275,7 @@ void factor_vm::find_data_references(cell look_for)
 
 	cell obj;
 
-	while((obj = next_object()) != F)
+	while(to_boolean(obj = next_object()))
 	{
 		data_references_finder finder(look_for,obj,this);
 		do_slots(UNTAG(obj),finder);
diff --git a/vm/dispatch.cpp b/vm/dispatch.cpp
index 03323f811d..23b0b80765 100755
--- a/vm/dispatch.cpp
+++ b/vm/dispatch.cpp
@@ -15,14 +15,14 @@ cell factor_vm::search_lookup_alist(cell table, cell klass)
 			index -= 2;
 	}
 
-	return F;
+	return false_object;
 }
 
 cell factor_vm::search_lookup_hash(cell table, cell klass, cell hashcode)
 {
 	array *buckets = untag<array>(table);
 	cell bucket = array_nth(buckets,hashcode & (array_capacity(buckets) - 1));
-	if(tagged<object>(bucket).type_p(WORD_TYPE) || bucket == F)
+	if(tagged<object>(bucket).type_p(WORD_TYPE) || !to_boolean(bucket))
 		return bucket;
 	else
 		return search_lookup_alist(bucket,klass);
@@ -56,12 +56,12 @@ cell factor_vm::lookup_tuple_method(cell obj, cell methods)
 
 		if(tagged<object>(echelon_methods).type_p(WORD_TYPE))
 			return echelon_methods;
-		else if(echelon_methods != F)
+		else if(to_boolean(echelon_methods))
 		{
 			cell klass = nth_superclass(layout,echelon);
 			cell hashcode = untag_fixnum(nth_hashcode(layout,echelon));
 			cell result = search_lookup_hash(echelon_methods,klass,hashcode);
-			if(result != F)
+			if(to_boolean(result))
 				return result;
 		}
 
@@ -69,7 +69,7 @@ cell factor_vm::lookup_tuple_method(cell obj, cell methods)
 	}
 
 	critical_error("Cannot find tuple method",methods);
-	return F;
+	return false_object;
 }
 
 cell factor_vm::lookup_hi_tag_method(cell obj, cell methods)
diff --git a/vm/errors.cpp b/vm/errors.cpp
index a3c0242d7e..a1fc71ffbc 100755
--- a/vm/errors.cpp
+++ b/vm/errors.cpp
@@ -29,7 +29,7 @@ void factor_vm::throw_error(cell error, stack_frame *callstack_top)
 {
 	/* If the error handler is set, we rewind any C stack frames and
 	pass the error to user-space. */
-	if(!current_gc && userenv[BREAK_ENV] != F)
+	if(!current_gc && to_boolean(userenv[BREAK_ENV]))
 	{
 		/* If error was thrown during heap scan, we re-enable the GC */
 		gc_off = false;
@@ -80,7 +80,7 @@ void factor_vm::type_error(cell type, cell tagged)
 
 void factor_vm::not_implemented_error()
 {
-	general_error(ERROR_NOT_IMPLEMENTED,F,F,NULL);
+	general_error(ERROR_NOT_IMPLEMENTED,false_object,false_object,NULL);
 }
 
 /* Test if 'fault' is in the guard page at the top or bottom (depending on
@@ -97,32 +97,32 @@ bool factor_vm::in_page(cell fault, cell area, cell area_size, int offset)
 void factor_vm::memory_protection_error(cell addr, stack_frame *native_stack)
 {
 	if(in_page(addr, ds_bot, 0, -1))
-		general_error(ERROR_DS_UNDERFLOW,F,F,native_stack);
+		general_error(ERROR_DS_UNDERFLOW,false_object,false_object,native_stack);
 	else if(in_page(addr, ds_bot, ds_size, 0))
-		general_error(ERROR_DS_OVERFLOW,F,F,native_stack);
+		general_error(ERROR_DS_OVERFLOW,false_object,false_object,native_stack);
 	else if(in_page(addr, rs_bot, 0, -1))
-		general_error(ERROR_RS_UNDERFLOW,F,F,native_stack);
+		general_error(ERROR_RS_UNDERFLOW,false_object,false_object,native_stack);
 	else if(in_page(addr, rs_bot, rs_size, 0))
-		general_error(ERROR_RS_OVERFLOW,F,F,native_stack);
+		general_error(ERROR_RS_OVERFLOW,false_object,false_object,native_stack);
 	else if(in_page(addr, nursery.end, 0, 0))
 		critical_error("allot_object() missed GC check",0);
 	else
-		general_error(ERROR_MEMORY,allot_cell(addr),F,native_stack);
+		general_error(ERROR_MEMORY,allot_cell(addr),false_object,native_stack);
 }
 
 void factor_vm::signal_error(int signal, stack_frame *native_stack)
 {
-	general_error(ERROR_SIGNAL,tag_fixnum(signal),F,native_stack);
+	general_error(ERROR_SIGNAL,tag_fixnum(signal),false_object,native_stack);
 }
 
 void factor_vm::divide_by_zero_error()
 {
-	general_error(ERROR_DIVIDE_BY_ZERO,F,F,NULL);
+	general_error(ERROR_DIVIDE_BY_ZERO,false_object,false_object,NULL);
 }
 
 void factor_vm::fp_trap_error(unsigned int fpu_status, stack_frame *signal_callstack_top)
 {
-	general_error(ERROR_FP_TRAP,tag_fixnum(fpu_status),F,signal_callstack_top);
+	general_error(ERROR_FP_TRAP,tag_fixnum(fpu_status),false_object,signal_callstack_top);
 }
 
 void factor_vm::primitive_call_clear()
diff --git a/vm/factor.cpp b/vm/factor.cpp
index 8b1202ddb0..5548ebd610 100755
--- a/vm/factor.cpp
+++ b/vm/factor.cpp
@@ -100,7 +100,7 @@ void factor_vm::do_stage1_init()
 	fflush(stdout);
 
 	compile_all_words();
-	userenv[STAGE2_ENV] = T;
+	userenv[STAGE2_ENV] = true_object;
 
 	print_string("done\n");
 	fflush(stdout);
@@ -148,17 +148,17 @@ void factor_vm::init_factor(vm_parameters *p)
 
 	init_profiler();
 
-	userenv[CPU_ENV] = allot_alien(F,(cell)FACTOR_CPU_STRING);
-	userenv[OS_ENV] = allot_alien(F,(cell)FACTOR_OS_STRING);
+	userenv[CPU_ENV] = allot_alien(false_object,(cell)FACTOR_CPU_STRING);
+	userenv[OS_ENV] = allot_alien(false_object,(cell)FACTOR_OS_STRING);
 	userenv[CELL_SIZE_ENV] = tag_fixnum(sizeof(cell));
-	userenv[EXECUTABLE_ENV] = allot_alien(F,(cell)p->executable_path);
-	userenv[ARGS_ENV] = F;
-	userenv[EMBEDDED_ENV] = F;
+	userenv[EXECUTABLE_ENV] = allot_alien(false_object,(cell)p->executable_path);
+	userenv[ARGS_ENV] = false_object;
+	userenv[EMBEDDED_ENV] = false_object;
 
 	/* We can GC now */
 	gc_off = false;
 
-	if(userenv[STAGE2_ENV] == F)
+	if(!to_boolean(userenv[STAGE2_ENV]))
 		do_stage1_init();
 }
 
@@ -169,7 +169,7 @@ void factor_vm::pass_args_to_factor(int argc, vm_char **argv)
 	int i;
 
 	for(i = 1; i < argc; i++){
-		args.add(allot_alien(F,(cell)argv[i]));
+		args.add(allot_alien(false_object,(cell)argv[i]));
 	}
 
 	args.trim();
diff --git a/vm/image.cpp b/vm/image.cpp
index 05e0d66724..cb598a18c3 100755
--- a/vm/image.cpp
+++ b/vm/image.cpp
@@ -8,7 +8,7 @@ void factor_vm::init_objects(image_header *h)
 {
 	memcpy(userenv,h->userenv,sizeof(userenv));
 
-	T = h->t;
+	true_object = h->true_object;
 	bignum_zero = h->bignum_zero;
 	bignum_pos_one = h->bignum_pos_one;
 	bignum_neg_one = h->bignum_neg_one;
@@ -88,13 +88,13 @@ bool factor_vm::save_image(const vm_char *filename)
 	h.code_relocation_base = code->seg->start;
 	h.code_size = code->heap_size();
 
-	h.t = T;
+	h.true_object = true_object;
 	h.bignum_zero = bignum_zero;
 	h.bignum_pos_one = bignum_pos_one;
 	h.bignum_neg_one = bignum_neg_one;
 
 	for(cell i = 0; i < USER_ENV; i++)
-		h.userenv[i] = (save_env_p(i) ? userenv[i] : F);
+		h.userenv[i] = (save_env_p(i) ? userenv[i] : false_object);
 
 	bool ok = true;
 
@@ -132,7 +132,7 @@ void factor_vm::primitive_save_image_and_exit()
 	/* strip out userenv data which is set on startup anyway */
 	for(cell i = 0; i < USER_ENV; i++)
 	{
-		if(!save_env_p(i)) userenv[i] = F;
+		if(!save_env_p(i)) userenv[i] = false_object;
 	}
 
 	gc(collect_full_op,
@@ -184,7 +184,7 @@ void factor_vm::fixup_quotation(quotation *quot, cell code_relocation_base)
 
 void factor_vm::fixup_alien(alien *d)
 {
-	if(d->base == F) d->expired = T;
+	if(!to_boolean(d->base)) d->expired = true_object;
 }
 
 struct stack_frame_fixupper {
@@ -273,7 +273,7 @@ void factor_vm::relocate_data(cell data_relocation_base, cell code_relocation_ba
 	for(cell i = 0; i < USER_ENV; i++)
 		data_fixup(&userenv[i],data_relocation_base);
 
-	data_fixup(&T,data_relocation_base);
+	data_fixup(&true_object,data_relocation_base);
 	data_fixup(&bignum_zero,data_relocation_base);
 	data_fixup(&bignum_pos_one,data_relocation_base);
 	data_fixup(&bignum_neg_one,data_relocation_base);
@@ -350,7 +350,7 @@ void factor_vm::load_image(vm_parameters *p)
 	relocate_code(h.data_relocation_base);
 
 	/* Store image path name */
-	userenv[IMAGE_ENV] = allot_alien(F,(cell)p->image_path);
+	userenv[IMAGE_ENV] = allot_alien(false_object,(cell)p->image_path);
 }
 
 }
diff --git a/vm/image.hpp b/vm/image.hpp
index f071185852..8a7080110c 100755
--- a/vm/image.hpp
+++ b/vm/image.hpp
@@ -17,7 +17,7 @@ struct image_header {
 	/* size of code heap */
 	cell code_size;
 	/* tagged pointer to t singleton */
-	cell t;
+	cell true_object;
 	/* tagged pointer to bignum 0 */
 	cell bignum_zero;
 	/* tagged pointer to bignum 1 */
diff --git a/vm/io.cpp b/vm/io.cpp
index 8e6eff730e..d5cfc1745c 100755
--- a/vm/io.cpp
+++ b/vm/io.cpp
@@ -16,9 +16,9 @@ normal operation. */
 
 void factor_vm::init_c_io()
 {
-	userenv[STDIN_ENV] = allot_alien(F,(cell)stdin);
-	userenv[STDOUT_ENV] = allot_alien(F,(cell)stdout);
-	userenv[STDERR_ENV] = allot_alien(F,(cell)stderr);
+	userenv[STDIN_ENV] = allot_alien(false_object,(cell)stdin);
+	userenv[STDOUT_ENV] = allot_alien(false_object,(cell)stdout);
+	userenv[STDERR_ENV] = allot_alien(false_object,(cell)stderr);
 }
 
 void factor_vm::io_error()
@@ -28,7 +28,7 @@ void factor_vm::io_error()
 		return;
 #endif
 
-	general_error(ERROR_IO,tag_fixnum(errno),F,NULL);
+	general_error(ERROR_IO,tag_fixnum(errno),false_object,NULL);
 }
 
 void factor_vm::primitive_fopen()
@@ -63,7 +63,7 @@ void factor_vm::primitive_fgetc()
 		{
 			if(feof(file))
 			{
-				dpush(F);
+				dpush(false_object);
 				break;
 			}
 			else
@@ -97,7 +97,7 @@ void factor_vm::primitive_fread()
 		{
 			if(feof(file))
 			{
-				dpush(F);
+				dpush(false_object);
 				break;
 			}
 			else
diff --git a/vm/jit.cpp b/vm/jit.cpp
index 77a311cb24..1a35cabbaf 100644
--- a/vm/jit.cpp
+++ b/vm/jit.cpp
@@ -103,7 +103,7 @@ code_block *jit::to_code_block()
 	return parent_vm->add_code_block(
 		type,
 		code.elements.value(),
-		F, /* no labels */
+		false_object, /* no labels */
 		owner.value(),
 		relocation.elements.value(),
 		literals.elements.value());
diff --git a/vm/layouts.hpp b/vm/layouts.hpp
index 2fba97d747..aef8b1b668 100644
--- a/vm/layouts.hpp
+++ b/vm/layouts.hpp
@@ -46,9 +46,6 @@ inline static cell align8(cell a)
 #define OBJECT_TYPE 6
 #define TUPLE_TYPE 7
 
-/* Canonical F object */
-#define F F_TYPE
-
 #define HEADER_TYPE 8 /* anything less than this is a tag */
 
 #define GC_COLLECTED 5 /* can be anything other than FIXNUM_TYPE */
@@ -78,9 +75,12 @@ enum
 	FP_TRAP_INEXACT           = 1 << 4,
 };
 
+/* What Factor calls 'f' */
+static const cell false_object = F_TYPE;
+
 inline static bool immediate_p(cell obj)
 {
-	return (obj == F || TAG(obj) == FIXNUM_TYPE);
+	return (obj == false_object || TAG(obj) == FIXNUM_TYPE);
 }
 
 inline static fixnum untag_fixnum(cell tagged)
diff --git a/vm/math.cpp b/vm/math.cpp
index e4caa0f5ca..679cdae166 100755
--- a/vm/math.cpp
+++ b/vm/math.cpp
@@ -285,7 +285,7 @@ void factor_vm::primitive_str_to_float()
 	if(end == c_str + capacity - 1)
 		drepl(allot_float(f));
 	else
-		drepl(F);
+		drepl(false_object);
 }
 
 void factor_vm::primitive_float_to_str()
diff --git a/vm/os-macosx.mm b/vm/os-macosx.mm
index 3aa001774b..96f169bbcf 100644
--- a/vm/os-macosx.mm
+++ b/vm/os-macosx.mm
@@ -13,7 +13,7 @@ NS_DURING
 		c_to_factor(quot,this);
 		NS_VOIDRETURN;
 NS_HANDLER
-		dpush(allot_alien(F,(cell)localException));
+		dpush(allot_alien(false_object,(cell)localException));
 		quot = userenv[COCOA_EXCEPTION_ENV];
 		if(!tagged<object>(quot).type_p(QUOTATION_TYPE))
 		{
diff --git a/vm/os-unix.cpp b/vm/os-unix.cpp
index 70d7e395de..2f9d5a3c89 100644
--- a/vm/os-unix.cpp
+++ b/vm/os-unix.cpp
@@ -72,7 +72,7 @@ void *factor_vm::ffi_dlsym(dll *dll, symbol_char *symbol)
 void factor_vm::ffi_dlclose(dll *dll)
 {
 	if(dlclose(dll->dll))
-		general_error(ERROR_FFI,F,F,NULL);
+		general_error(ERROR_FFI,false_object,false_object,NULL);
 	dll->dll = NULL;
 }
 
diff --git a/vm/quotations.cpp b/vm/quotations.cpp
index 60fdce1003..4c15d2d57e 100755
--- a/vm/quotations.cpp
+++ b/vm/quotations.cpp
@@ -88,7 +88,7 @@ bool quotation_jit::stack_frame_p()
 		switch(tagged<object>(obj).type())
 		{
 		case WORD_TYPE:
-			if(parent_vm->untag<word>(obj)->subprimitive == F)
+			if(!parent_vm->to_boolean(parent_vm->untag<word>(obj)->subprimitive))
 				return true;
 			break;
 		case QUOTATION_TYPE:
@@ -149,7 +149,7 @@ void quotation_jit::iterate_quotation()
 		{
 		case WORD_TYPE:
 			/* Intrinsics */
-			if(obj.as<word>()->subprimitive != F)
+			if(parent_vm->to_boolean(obj.as<word>()->subprimitive))
 				emit_subprimitive(obj.value());
 			/* The (execute) primitive is special-cased */
 			else if(obj.value() == parent_vm->userenv[JIT_EXECUTE_WORD])
@@ -313,8 +313,8 @@ void factor_vm::primitive_array_to_quotation()
 {
 	quotation *quot = allot<quotation>(sizeof(quotation));
 	quot->array = dpeek();
-	quot->cached_effect = F;
-	quot->cache_counter = F;
+	quot->cached_effect = false_object;
+	quot->cache_counter = false_object;
 	quot->xt = (void *)lazy_jit_compile;
 	quot->code = NULL;
 	drepl(tag<quotation>(quot));
diff --git a/vm/strings.cpp b/vm/strings.cpp
index ecfc84ebef..d7434fe660 100644
--- a/vm/strings.cpp
+++ b/vm/strings.cpp
@@ -35,7 +35,9 @@ void factor_vm::set_string_nth_slow(string *str_, cell index, cell ch)
 
 	str->data()[index] = ((ch & 0x7f) | 0x80);
 
-	if(str->aux == F)
+	if(to_boolean(str->aux))
+		aux = untag<byte_array>(str->aux);
+	else
 	{
 		/* We don't need to pre-initialize the
 		byte array with any data, since we
@@ -48,8 +50,6 @@ void factor_vm::set_string_nth_slow(string *str_, cell index, cell ch)
 		str->aux = tag<byte_array>(aux);
 		write_barrier(&str->aux);
 	}
-	else
-		aux = untag<byte_array>(str->aux);
 
 	aux->data<u16>()[index] = ((ch >> 7) ^ 1);
 }
@@ -69,8 +69,8 @@ string *factor_vm::allot_string_internal(cell capacity)
 	string *str = allot<string>(string_size(capacity));
 
 	str->length = tag_fixnum(capacity);
-	str->hashcode = F;
-	str->aux = F;
+	str->hashcode = false_object;
+	str->aux = false_object;
 
 	return str;
 }
@@ -109,7 +109,7 @@ void factor_vm::primitive_string()
 bool factor_vm::reallot_string_in_place_p(string *str, cell capacity)
 {
 	return nursery.contains_p(str)
-		&& (str->aux == F || nursery.contains_p(untag<byte_array>(str->aux)))
+		&& (!to_boolean(str->aux) || nursery.contains_p(untag<byte_array>(str->aux)))
 		&& capacity <= string_capacity(str);
 }
 
@@ -121,7 +121,7 @@ string* factor_vm::reallot_string(string *str_, cell capacity)
 	{
 		str->length = tag_fixnum(capacity);
 
-		if(str->aux != F)
+		if(to_boolean(str->aux))
 		{
 			byte_array *aux = untag<byte_array>(str->aux);
 			aux->capacity = tag_fixnum(capacity * 2);
@@ -139,7 +139,7 @@ string* factor_vm::reallot_string(string *str_, cell capacity)
 
 		memcpy(new_str->data(),str->data(),to_copy);
 
-		if(str->aux != F)
+		if(to_boolean(str->aux))
 		{
 			byte_array *new_aux = allot_byte_array(capacity * sizeof(u16));
 
diff --git a/vm/tuples.cpp b/vm/tuples.cpp
index 5fdde6596e..2d195ea13b 100755
--- a/vm/tuples.cpp
+++ b/vm/tuples.cpp
@@ -18,7 +18,7 @@ void factor_vm::primitive_tuple()
 	tuple *t = allot_tuple(layout.value());
 	fixnum i;
 	for(i = tuple_size(layout.untagged()) - 1; i >= 0; i--)
-		t->data()[i] = F;
+		t->data()[i] = false_object;
 
 	dpush(tag<tuple>(t));
 }
diff --git a/vm/vm.hpp b/vm/vm.hpp
index c3d71dc6f2..d232d6153d 100755
--- a/vm/vm.hpp
+++ b/vm/vm.hpp
@@ -26,8 +26,8 @@ struct factor_vm
 	/* Pooling unused contexts to make callbacks cheaper */
 	context *unused_contexts;
 
-	/* Canonical T object. It's just a word */
-	cell T;
+	/* Canonical truth value. In Factor, 't' */
+	cell true_object;
 
 	/* Is call counting enabled? */
 	bool profiling_p;
diff --git a/vm/words.cpp b/vm/words.cpp
index 72460a64b9..6193a5c93c 100644
--- a/vm/words.cpp
+++ b/vm/words.cpp
@@ -14,11 +14,11 @@ word *factor_vm::allot_word(cell name_, cell vocab_, cell hashcode_)
 	new_word->vocabulary = vocab.value();
 	new_word->name = name.value();
 	new_word->def = userenv[UNDEFINED_ENV];
-	new_word->props = F;
+	new_word->props = false_object;
 	new_word->counter = tag_fixnum(0);
-	new_word->pic_def = F;
-	new_word->pic_tail_def = F;
-	new_word->subprimitive = F;
+	new_word->pic_def = false_object;
+	new_word->pic_tail_def = false_object;
+	new_word->subprimitive = false_object;
 	new_word->profiling = NULL;
 	new_word->code = NULL;